在SAMD21上将SPI的SERCOM引脚设置为主机对面

如何解决在SAMD21上将SPI的SERCOM引脚设置为主机对面

我正试图将SAMD21芯片设为SPI从设备。

我有以下针脚：

PB10作为MOSI
PB11作为SCK
PA10为SS
PA12作为MISO

这些引脚大多数属于SERCOM4

但是，当我按如下所示设置它们时，它们不能正常工作：

 PORT->Group[PORTB].PINCFG[10].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PA12 Arduino PIN22
 PORT->Group[PORTA].PMUX[6].bit.PMUXE = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)
 PORT->Group[PORTB].PINCFG[11].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PB09 Arduino PIN16
 PORT->Group[PORTB].PMUX[4].bit.PMUXO = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)
 PORT->Group[PORTA].PINCFG[10].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PB10 Arduino PIN23
 PORT->Group[PORTB].PMUX[5].bit.PMUXE = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)
 PORT->Group[PORTA].PINCFG[12].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PB11 Arduino PIN24
 PORT->Group[PORTB].PMUX[5].bit.PMUXO = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)

我使用的是 https://github.com/lenvm/SercomSPISlave

我使用arduino IDE和SAMD对芯片进行编程：M0或M0 Pro（原始）板布局。

根据文档说明的针脚：

| 1 | 1
| 22 | 1 | PA12 | MISO | EIC / EXTINT [12] SERCOM2 / PAD [0] * SERCOM4 / PAD [0] TCC2 / WO [0] TCC0 / WO [6]
| 23 | 4 | PB10 | MOSI | EIC / EXTINT [10] * SERCOM4 / PAD [2] TC5 / WO [0] TCC0 / WO [4]
| 24 | 3 | PB11 | SCK | EIC / EXTINT [11] * SERCOM4 / PAD [3] TC5 / WO [1] TCC0 / WO [5]