SPIM — Serial peripheral interface master with EasyDMA

The SPI master can communicate with multiple SPI slaves using individual chip select signals for each slave.

Listed here are the main features for the SPIM

Figure 1. SPIM — SPI master with EasyDMA
SPIM — SPI master with EasyDMA

SPI master transaction sequence

An SPI master transaction is started by triggering the START task. When started, a number of bytes will be transmitted/received on MOSI/MISO.

The following figure illustrates an SPI master transaction:

Figure 2. SPI master transaction
SPI master transaction: START task, ENDTX, and ENDRX events

The ENDTX is generated when all bytes in buffer TXD.PTR are transmitted. The number of bytes in the transmit buffer is specified in register TXD.MAXCNT. The ENDRX event will be generated when buffer RXD.PTR is full, that is when the number of bytes specified in register RXD.MAXCNT have been received. The transaction stops automatically after all bytes have been transmitted/received. When the maximum number of bytes in receive buffer is larger than the number of bytes in the transmit buffer, the contents of register ORC will be transmitted after the last byte in the transmit buffer has been transmitted.

The END event will be generated after both the ENDRX and ENDTX events have been generated.

The SPI master can be stopped in the middle of a transaction by triggering the STOP task. When triggering the STOP task the SPIM will complete the transmission/reception of the current byte before stopping. A STOPPED event is generated when the SPI master has stopped.

If the ENDTX event has not already been generated when the SPI master has come to a stop, the ENDTX event will be generated even if all bytes in the buffer TXD.PTR have not been transmitted.

If the ENDRX event has not already been generated when the SPI master has come to a stop, the ENDRX event will be generated even if the buffer RXD.PTR is not full.

A transaction can be suspended and resumed using the SUSPEND and RESUME tasks, receptively. When the SUSPEND task is triggered the SPI master will complete transmitting and receiving the current ongoing byte before it is suspended.

D/CX functionality

Some SPI slaves, for example display drivers, require an additional signal from the SPI master to distinguish between command and data bytes. For display drivers this line is often called D/CX.

The SPIM provides support for such a D/CX output line. The D/CX line is set low during transmission of command bytes and high during transmission of data bytes.

The D/CX pin number is selected using PSELDCX and the number of command bytes preceding the data bytes is configured using DCXCNT.

It is not allowed to write to the DCXCNT during an ongoing transmission.

Figure 3. D/CX example. SPIM.DCXCNT = 1.

Pin configuration

The SCK, CSN, DCX, MOSI, and MISO signals associated with the SPIM are mapped to physical pins according to the configuration specified in the PSEL.n registers.

The contents of registers PSEL.SCK, PSEL.CSN, PSELDCX, PSEL.MOSI and PSEL.MISO are only used when the SPIM is enabled and retained only as long as the device is in System ON mode. The PSEL.n registers can only be configured when the SPIM is disabled. Enabling/disabling is done using register ENABLE.

To ensure correct behavior, the pins used by the SPIM must be configured in the GPIO peripheral as described in GPIO configuration before the SPIM is enabled.

Only one peripheral can be assigned to drive a particular GPIO pin at a time. Failing to do so may result in unpredictable behavior.

Table 1. GPIO configuration
SPI master signal SPI master pin Direction Output value Comments
SCK As specified in PSEL.SCK Output Same as CONFIG.CPOL  
CSN As specified in PSEL.CSN Output Same as CONFIG.CPOL  
DCX As specified in PSELDCX Output 1  
MOSI As specified in PSEL.MOSI Output 0  
MISO As specified in PSEL.MISO Input Not applicable  

Some SPIM instances do not support automatic control of CSN, and for those the available GPIO pins need to be used to control CSN directly. See Instances for information about what features are supported in the various SPIM instances.

The SPIM supports SPI modes 0 through 3. The clock polarity (CPOL) and the clock phase (CPHA) are configured in register CONFIG.

Table 2. SPI modes
Mode Clock polarity Clock phase
  CPOL CPHA
SPI_MODE0 0 (Active High) 0 (Leading)
SPI_MODE1 0 (Active High) 1 (Trailing)
SPI_MODE2 1 (Active Low) 0 (Leading)
SPI_MODE3 1 (Active Low) 1 (Trailing)

EasyDMA

The SPIM implements EasyDMA for accessing RAM without CPU involvement.

If RXD.PTR and TXD.PTR are not pointing to Data RAM region, an EasyDMA transfer may result in a HardFault or RAM corruption. See Memory for more information about the different memory regions.

If several AHB bus masters try to access the same AHB slave at the same time, AHB bus congestion might occur. The SPIM is such an AHB master, and when congestion occurs the SPIM might have to wait for access to RAM to be granted. If the SPIM has to wait for bus access the transaction will be temporary stalled, but resume once the SPIM is granted access to the bus. See the AHB multilayer for more information on this subject. Note that some SPIM instances do not support this stalling mechanism. Refer to Instances for information about what features are supported in the various instances.

EasyDMA array list

The EasyDMA array list can be represented by the data structure ArrayList_type as illustrated in the code example.


	#define BUFFER_SIZE  4
  
  typedef struct ArrayList
  {
    uint8_t buffer[BUFFER_SIZE];
  } ArrayList_type;

  ArrayList_type MyArrayList[3];

  //replace 'Channel' below by the specific data channel you want to use,
  //         for instance 'NRF_SPIM->RXD', 'NRF_TWIM->RXD', etc.
  Channel.MAXCNT = BUFFER_SIZE;
  Channel.PTR = &MyArrayList;
  

This data structure includes only a buffer with size equal to Channel.MAXCNT. EasyDMA will use the Channel.MAXCNT register to determine when the buffer is full. Replace 'Channel' by the specific data channel you want to use, for instance 'NRF_SPIM->RXD', 'NRF_SPIM->TXD', 'NRF_TWIM->RXD', etc.

The Channel.MAXCNT register cannot be specified larger than the actual size of the buffer. If Channel.MAXCNT is specified larger than the size of the buffer, the EasyDMA channel may overflow the buffer.

This array list does not provide a mechanism to explicitly specify where the next item in the list is located. Instead, it assumes that the list is organized as a linear array where items are located one after the other in RAM.

Figure 4. EasyDMA array list
EasyDMA array list

Low power

When putting the system in low power and the peripheral is not needed, lowest possible power consumption is achieved by stopping, and then disabling the peripheral.

The STOP task may not be always needed (the peripheral might already be stopped), but if it is sent, software shall wait until the STOPPED event was received as a response before disabling the peripheral through the ENABLE register.

Registers

Table 3. Instances
Base address Peripheral Instance Description Configuration
0x40003000 SPIM SPIM0

SPI master 0

Not supported: > 8 Mbps data rate, CSNPOL register, DCX functionality, IFTIMING.x registers, hardware CSN control (PSEL.CSN), stalling mechanism during AHB bus contention.

 
0x40004000 SPIM SPIM1

SPI master 1

Not supported: > 8 Mbps data rate, CSNPOL register, DCX functionality, IFTIMING.x registers, hardware CSN control (PSEL.CSN), stalling mechanism during AHB bus contention.

 
0x40023000 SPIM SPIM2

SPI master 2

Not supported: > 8 Mbps data rate, CSNPOL register, DCX functionality, IFTIMING.x registers, hardware CSN control (PSEL.CSN), stalling mechanism during AHB bus contention.

 
0x4002F000 SPIM SPIM3

SPI master 3

   
Table 4. Register overview
Register Offset Description
TASKS_START 0x010

Start SPI transaction

 
TASKS_STOP 0x014

Stop SPI transaction

 
TASKS_SUSPEND 0x01C

Suspend SPI transaction

 
TASKS_RESUME 0x020

Resume SPI transaction

 
EVENTS_STOPPED 0x104

SPI transaction has stopped

 
EVENTS_ENDRX 0x110

End of RXD buffer reached

 
EVENTS_END 0x118

End of RXD buffer and TXD buffer reached

 
EVENTS_ENDTX 0x120

End of TXD buffer reached

 
EVENTS_STARTED 0x14C

Transaction started

 
SHORTS 0x200

Shortcut register

 
INTENSET 0x304

Enable interrupt

 
INTENCLR 0x308

Disable interrupt

 
STALLSTAT 0x400

Stall status for EasyDMA RAM accesses. The fields in this register is set to STALL by hardware whenever a stall occurres and can be cleared (set to NOSTALL) by the CPU.

 
ENABLE 0x500

Enable SPIM

 
PSEL.SCK 0x508

Pin select for SCK

 
PSEL.MOSI 0x50C

Pin select for MOSI signal

 
PSEL.MISO 0x510

Pin select for MISO signal

 
PSEL.CSN 0x514

Pin select for CSN

 
FREQUENCY 0x524

SPI frequency. Accuracy depends on the HFCLK source selected.

 
RXD.PTR 0x534

Data pointer

 
RXD.MAXCNT 0x538

Maximum number of bytes in receive buffer

 
RXD.AMOUNT 0x53C

Number of bytes transferred in the last transaction

 
RXD.LIST 0x540

EasyDMA list type

 
TXD.PTR 0x544

Data pointer

 
TXD.MAXCNT 0x548

Number of bytes in transmit buffer

 
TXD.AMOUNT 0x54C

Number of bytes transferred in the last transaction

 
TXD.LIST 0x550

EasyDMA list type

 
CONFIG 0x554

Configuration register

 
IFTIMING.RXDELAY 0x560

Sample delay for input serial data on MISO

 
IFTIMING.CSNDUR 0x564

Minimum duration between edge of CSN and edge of SCK and minimum duration CSN must stay high between transactions

 
CSNPOL 0x568

Polarity of CSN output

 
PSELDCX 0x56C

Pin select for DCX signal

 
DCXCNT 0x570

DCX configuration

 
ORC 0x5C0

Byte transmitted after TXD.MAXCNT bytes have been transmitted in the case when RXD.MAXCNT is greater than TXD.MAXCNT

 

SHORTS

Address offset: 0x200

Shortcut register

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                             A                                  
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

END_START

   

Shortcut between END event and START task

See EVENTS_END and TASKS_START

     

Disabled

0

Disable shortcut

     

Enabled

1

Enable shortcut

INTENSET

Address offset: 0x304

Enable interrupt

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                         E                     D   C   B     A  
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

STOPPED

   

Write '1' to enable interrupt for STOPPED event

See EVENTS_STOPPED

     

Set

1

Enable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

B RW

ENDRX

   

Write '1' to enable interrupt for ENDRX event

See EVENTS_ENDRX

     

Set

1

Enable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

C RW

END

   

Write '1' to enable interrupt for END event

See EVENTS_END

     

Set

1

Enable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

D RW

ENDTX

   

Write '1' to enable interrupt for ENDTX event

See EVENTS_ENDTX

     

Set

1

Enable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

E RW

STARTED

   

Write '1' to enable interrupt for STARTED event

See EVENTS_STARTED

     

Set

1

Enable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

INTENCLR

Address offset: 0x308

Disable interrupt

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                         E                     D   C   B     A  
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

STOPPED

   

Write '1' to disable interrupt for STOPPED event

See EVENTS_STOPPED

     

Clear

1

Disable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

B RW

ENDRX

   

Write '1' to disable interrupt for ENDRX event

See EVENTS_ENDRX

     

Clear

1

Disable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

C RW

END

   

Write '1' to disable interrupt for END event

See EVENTS_END

     

Clear

1

Disable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

D RW

ENDTX

   

Write '1' to disable interrupt for ENDTX event

See EVENTS_ENDTX

     

Clear

1

Disable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

E RW

STARTED

   

Write '1' to disable interrupt for STARTED event

See EVENTS_STARTED

     

Clear

1

Disable

     

Disabled

0

Read: Disabled

     

Enabled

1

Read: Enabled

STALLSTAT

Address offset: 0x400

Stall status for EasyDMA RAM accesses. The fields in this register is set to STALL by hardware whenever a stall occurres and can be cleared (set to NOSTALL) by the CPU.

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                             B A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

TX

 

[1..0]

Stall status for EasyDMA RAM reads

     

NOSTALL

0

No stall

     

STALL

1

A stall has occurred

B RW

RX

 

[1..0]

Stall status for EasyDMA RAM writes

     

NOSTALL

0

No stall

     

STALL

1

A stall has occurred

ENABLE

Address offset: 0x500

Enable SPIM

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                         A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

ENABLE

   

Enable or disable SPIM

     

Disabled

0

Disable SPIM

     

Enabled

7

Enable SPIM

PSEL.SCK

Address offset: 0x508

Pin select for SCK

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID C                                                  

B

A A A A A
Reset 0xFFFFFFFF 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
ID RW Field Value ID Value Description
A RW

PIN

 

[0..31]

Pin number

B RW

PORT

 

[0..1]

Port number

C RW

CONNECT

   

Connection

     

Disconnected

1

Disconnect

     

Connected

0

Connect

PSEL.MOSI

Address offset: 0x50C

Pin select for MOSI signal

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID C                                                  

B

A A A A A
Reset 0xFFFFFFFF 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
ID RW Field Value ID Value Description
A RW

PIN

 

[0..31]

Pin number

B RW

PORT

 

[0..1]

Port number

C RW

CONNECT

   

Connection

     

Disconnected

1

Disconnect

     

Connected

0

Connect

PSEL.MISO

Address offset: 0x510

Pin select for MISO signal

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID C                                                  

B

A A A A A
Reset 0xFFFFFFFF 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
ID RW Field Value ID Value Description
A RW

PIN

 

[0..31]

Pin number

B RW

PORT

 

[0..1]

Port number

C RW

CONNECT

   

Connection

     

Disconnected

1

Disconnect

     

Connected

0

Connect

PSEL.CSN

Address offset: 0x514

Pin select for CSN

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID C                                                  

B

A A A A A
Reset 0xFFFFFFFF 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
ID RW Field Value ID Value Description
A RW

PIN

 

[0..31]

Pin number

B RW

PORT

 

[0..1]

Port number

C RW

CONNECT

   

Connection

     

Disconnected

1

Disconnect

     

Connected

0

Connect

FREQUENCY

Address offset: 0x524

SPI frequency. Accuracy depends on the HFCLK source selected.

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A
Reset 0x04000000 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

FREQUENCY

   

SPI master data rate

     

K125

0x02000000

125 kbps

     

K250

0x04000000

250 kbps

     

K500

0x08000000

500 kbps

     

M1

0x10000000

1 Mbps

     

M2

0x20000000

2 Mbps

     

M4

0x40000000

4 Mbps

     

M8

0x80000000

8 Mbps

     

M16

0x0A000000

16 Mbps

     

M32

0x14000000

32 Mbps

RXD.PTR

Address offset: 0x534

Data pointer

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

PTR

   

Data pointer

Note: See the memory chapter for details about which memories are available for EasyDMA.

RXD.MAXCNT

Address offset: 0x538

Maximum number of bytes in receive buffer

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                 A A A A A A A A A A A A A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

MAXCNT

 

[1..0xffff]

Maximum number of bytes in receive buffer

RXD.AMOUNT

Address offset: 0x53C

Number of bytes transferred in the last transaction

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                 A A A A A A A A A A A A A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A R

AMOUNT

 

[1..0xffff]

Number of bytes transferred in the last transaction

RXD.LIST

Address offset: 0x540

EasyDMA list type

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                             A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

LIST

   

List type

     

Disabled

0

Disable EasyDMA list

     

ArrayList

1

Use array list

TXD.PTR

Address offset: 0x544

Data pointer

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

PTR

   

Data pointer

Note: See the memory chapter for details about which memories are available for EasyDMA.

TXD.MAXCNT

Address offset: 0x548

Number of bytes in transmit buffer

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                 A A A A A A A A A A A A A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

MAXCNT

 

[1..0xffff]

Maximum number of bytes in transmit buffer

TXD.AMOUNT

Address offset: 0x54C

Number of bytes transferred in the last transaction

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                 A A A A A A A A A A A A A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A R

AMOUNT

 

[1..0xffff]

Number of bytes transferred in the last transaction

TXD.LIST

Address offset: 0x550

EasyDMA list type

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                             A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

LIST

   

List type

     

Disabled

0

Disable EasyDMA list

     

ArrayList

1

Use array list

CONFIG

Address offset: 0x554

Configuration register

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                           C B A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

ORDER

   

Bit order

     

MsbFirst

0

Most significant bit shifted out first

     

LsbFirst

1

Least significant bit shifted out first

B RW

CPHA

   

Serial clock (SCK) phase

     

Leading

0

Sample on leading edge of clock, shift serial data on trailing edge

     

Trailing

1

Sample on trailing edge of clock, shift serial data on leading edge

C RW

CPOL

   

Serial clock (SCK) polarity

     

ActiveHigh

0

Active high

     

ActiveLow

1

Active low

IFTIMING.RXDELAY

Address offset: 0x560

Sample delay for input serial data on MISO

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                           A A A
Reset 0x00000002 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
ID RW Field Value ID Value Description
A RW

RXDELAY

 

[7..0]

Sample delay for input serial data on MISO. The value specifies the number of 64 MHz clock cycles (15.625 ns) delay from the the sampling edge of SCK (leading edge for CONFIG.CPHA = 0, trailing edge for CONFIG.CPHA = 1) until the input serial data is sampled. As en example, if RXDELAY = 0 and CONFIG.CPHA = 0, the input serial data is sampled on the rising edge of SCK.

IFTIMING.CSNDUR

Address offset: 0x564

Minimum duration between edge of CSN and edge of SCK and minimum duration CSN must stay high between transactions

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                 A A A A A A A A
Reset 0x00000002 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
ID RW Field Value ID Value Description
A RW

CSNDUR

 

[0xFF..0]

Minimum duration between edge of CSN and edge of SCK and minimum duration CSN must stay high between transactions. The value is specified in number of 64 MHz clock cycles (15.625 ns).

CSNPOL

Address offset: 0x568

Polarity of CSN output

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                               A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

CSNPOL

   

Polarity of CSN output

     

LOW

0

Active low (idle state high)

     

HIGH

1

Active high (idle state low)

PSELDCX

Address offset: 0x56C

Pin select for DCX signal

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID C                                                  

B

A A A A A
Reset 0xFFFFFFFF 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
ID RW Field Value ID Value Description
A RW

PIN

 

[0..31]

Pin number

B RW

PORT

 

[0..1]

Port number

C RW

CONNECT

   

Connection

     

Disconnected

1

Disconnect

     

Connected

0

Connect

DCXCNT

Address offset: 0x570

DCX configuration

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                         A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

DCXCNT

 

0x0..0xF

This register specifies the number of command bytes preceding the data bytes. The PSEL.DCX line will be low during transmission of command bytes and high during transmission of data bytes. Value 0xF indicates that all bytes are command bytes.

ORC

Address offset: 0x5C0

Byte transmitted after TXD.MAXCNT bytes have been transmitted in the case when RXD.MAXCNT is greater than TXD.MAXCNT

Bit number 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ID                                                 A A A A A A A A
Reset 0x00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ID RW Field Value ID Value Description
A RW

ORC

   

Byte transmitted after TXD.MAXCNT bytes have been transmitted in the case when RXD.MAXCNT is greater than TXD.MAXCNT.

Electrical specification

Timing specifications

Symbol Description Min. Typ. Max. Units
fSPIM

Bit rates for SPIM1

32 Mbps
tSPIM,START

Time from START task to transmission started

1 µs
tSPIM,CSCK

SCK period

125 ns
tSPIM,RSCK,LD

SCK rise time, standard drivea

tRF,25pF  
tSPIM,RSCK,HD

SCK rise time, high drivea

tHRF,25pF  
tSPIM,FSCK,LD

SCK fall time, standard drivea

tRF,25pF  
tSPIM,FSCK,HD

SCK fall time, high drivea

tHRF,25pF  
tSPIM,WHSCK

SCK high timea

(0.5*tCSCK) – tRSCK  
tSPIM,WLSCK

SCK low timea

(0.5*tCSCK) – tFSCK  
tSPIM,SUMI

MISO to CLK edge setup time

19 ns
tSPIM,HMI

CLK edge to MISO hold time

18 ns
tSPIM,VMO

CLK edge to MOSI valid, SCK frequency <= 8 MHz

59 ns
tSPIM,VMO,HS

CLK edge to MOSI valid, SCK frequency > 8 MHz

8 ns
tSPIM,HMO

MOSI hold time after CLK edge

20 ns
Figure 5. SPIM timing diagram
SPI master timing diagram

1 High bit rates may require GPIOs to be set as High Drive, see GPIO chapter for more details.
2 At 25pF load, including GPIO pin capacitance, see GPIO spec.

Documentation feedback | Developer Zone | Updated 2018-03-22