From 4c132614e136970cbd12d927bc6c52e2a7f0f070 Mon Sep 17 00:00:00 2001 From: Peter van der Burg Date: Fri, 21 May 2021 10:02:01 +1000 Subject: [PATCH] samd/samd_soc: Allow a board to configure the low-level MCU config. The board specific #defines will be moved to individual boards. --- ports/samd/samd_soc.c | 95 ++++++++++++++++++++++++------------------- ports/samd/samd_soc.h | 12 ------ 2 files changed, 53 insertions(+), 54 deletions(-) diff --git a/ports/samd/samd_soc.c b/ports/samd/samd_soc.c index a08d0de269..7f4df1bb1c 100644 --- a/ports/samd/samd_soc.c +++ b/ports/samd/samd_soc.c @@ -1,6 +1,12 @@ /* * This file is part of the MicroPython project, http://micropython.org/ * + * This file initialises the USB (tinyUSB) and USART (SERCOM). Board USART settings + * are set in 'boards//mpconfigboard.h. + * + * IMPORTANT: Please refer to "I/O Multiplexing and Considerations" chapters + * in device datasheets for I/O Pin functions and assignments. + * * The MIT License (MIT) * * Copyright (c) 2019 Damien P. George @@ -24,56 +30,53 @@ * THE SOFTWARE. */ +#include "py/runtime.h" +#include "modmachine.h" #include "samd_soc.h" #include "tusb.h" -static void uart0_init(void) { +// "MP" macros defined in "boards/$(BOARD)/mpconfigboard.h" +mp_obj_t machine_uart_init(void) { + // Firstly, assign alternate function SERCOM PADs to GPIO pins. + PORT->Group[MP_PIN_GRP].PINCFG[MP_TX_PIN].bit.PMUXEN = 1; // Enable + PORT->Group[MP_PIN_GRP].PINCFG[MP_RX_PIN].bit.PMUXEN = 1; // Enable + PORT->Group[MP_PIN_GRP].PMUX[MP_PERIPHERAL_MUX].reg = MP_PORT_FUNC; // Sets PMUXE & PMUXO in 1 hit. + uint32_t rxpo = MP_RXPO_PAD; // 1=Pad1,3=Pad3 Rx data + uint32_t txpo = MP_TXPO_PAD; // 0=pad0,1=Pad2 Tx data + + // Initialise the clocks #if defined(MCU_SAMD21) - - // SERCOM0, TX=PA06=PAD2, RX=PA07=PAD3, ALT-D - PORT->Group[0].PMUX[3].reg = 0x33; - PORT->Group[0].PINCFG[6].reg = 1; - PORT->Group[0].PINCFG[7].reg = 1; - - PM->APBCMASK.bit.SERCOM0_ = 1; - GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID_SERCOM0_CORE; + PM->APBCMASK.bit.MP_SERCOMx = 1; // Enable synchronous clock + GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | MP_SERCOM_GCLK_ID_x_CORE; // Select multiplexer generic clock source and enable. + // Wait while it updates synchronously. while (GCLK->STATUS.bit.SYNCBUSY) { } - - uint32_t rxpo = 3; - uint32_t txpo = 1; - #elif defined(MCU_SAMD51) - - // SERCOM3, TX=PA17=PAD0, RX=PA16=PAD1, ALT-D - PORT->Group[0].PMUX[8].reg = 0x33; - PORT->Group[0].PINCFG[16].reg = 1; - PORT->Group[0].PINCFG[17].reg = 1; - - // Use Generator 0 which is already enabled and switched to DFLL @ 48MHz - GCLK->PCHCTRL[SERCOM3_GCLK_ID_CORE].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN_GCLK0; - MCLK->APBBMASK.bit.SERCOM3_ = 1; - - uint32_t rxpo = 1; - uint32_t txpo = 2; - + GCLK->PCHCTRL[MP_SERCOM_GCLK_ID_x_CORE].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN_GCLK0; + MCLK->APBBMASK.bit.MP_SERCOMx = 1; #endif + // Setup the Peripheral. + // Reset (clear) the peripheral registers. while (USARTx->USART.SYNCBUSY.bit.SWRST) { } - USARTx->USART.CTRLA.bit.SWRST = 1; + USARTx->USART.CTRLA.bit.SWRST = 1; // Reset all Registers, disable peripheral while (USARTx->USART.SYNCBUSY.bit.SWRST) { } - USARTx->USART.CTRLA.reg = - SERCOM_USART_CTRLA_DORD - | SERCOM_USART_CTRLA_RXPO(rxpo) - | SERCOM_USART_CTRLA_TXPO(txpo) - | SERCOM_USART_CTRLA_MODE(1) + // Set the register bits as needed + // (CMODE (async),CHSIZE (8),FORM (no parity),SBMODE (1 stop) already 0). + USARTx->USART.CTRLA.reg = // USARTx = SERCOMx set in "boards/$(BOARD)/mpconfigboard.h" + SERCOM_USART_CTRLA_DORD // Data order + | SERCOM_USART_CTRLA_RXPO(rxpo) // Set Pad# + | SERCOM_USART_CTRLA_TXPO(txpo) // Set Pad# + | SERCOM_USART_CTRLA_MODE(1) // USART with internal clock ; - USARTx->USART.CTRLB.reg = SERCOM_USART_CTRLB_RXEN | SERCOM_USART_CTRLB_TXEN; + USARTx->USART.CTRLB.reg = SERCOM_USART_CTRLB_RXEN | SERCOM_USART_CTRLB_TXEN; // Enable Rx & Tx while (USARTx->USART.SYNCBUSY.bit.CTRLB) { } + + // Baud rate is clock dependant. #if CPU_FREQ == 8000000 uint32_t baud = 50437; // 115200 baud; 65536*(1 - 16 * 115200/8e6) #elif CPU_FREQ == 48000000 @@ -81,12 +84,26 @@ static void uart0_init(void) { #elif CPU_FREQ == 120000000 uint32_t baud = 64529; // 115200 baud; 65536*(1 - 16 * 115200/120e6) #endif - USARTx->USART.BAUD.bit.BAUD = baud; - USARTx->USART.CTRLA.bit.ENABLE = 1; + USARTx->USART.BAUD.bit.BAUD = baud; // Set Baud + USARTx->USART.CTRLA.bit.ENABLE = 1; // Enable the peripheral + // Wait for the Registers to update. while (USARTx->USART.SYNCBUSY.bit.ENABLE) { } + + return mp_const_none; } +// Disconnect SERCOM from GPIO pins. (Can't SWRST, as that will totally kill USART). +mp_obj_t machine_uart_deinit(void) { + // Reset + printf("Disabling the Alt-Funct, releasing the USART pins for GPIO... \n"); + PORT->Group[MP_PIN_GRP].PINCFG[MP_TX_PIN].bit.PMUXEN = 0; // Disable + PORT->Group[MP_PIN_GRP].PINCFG[MP_RX_PIN].bit.PMUXEN = 0; // Disable + + return mp_const_none; +} + + static void usb_init(void) { // Init USB clock #if defined(MCU_SAMD21) @@ -142,21 +159,15 @@ void samd_init(void) { while (GCLK->STATUS.bit.SYNCBUSY) { } - // Configure PA10 as output for LED - PORT->Group[0].DIRSET.reg = 1 << 10; - #elif defined(MCU_SAMD51) GCLK->GENCTRL[1].reg = 1 << GCLK_GENCTRL_DIV_Pos | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL; while (GCLK->SYNCBUSY.bit.GENCTRL1) { } - // Configure PA22 as output for LED - PORT->Group[0].DIRSET.reg = 1 << 22; - #endif SysTick_Config(CPU_FREQ / 1000); - uart0_init(); + machine_uart_init(); usb_init(); } diff --git a/ports/samd/samd_soc.h b/ports/samd/samd_soc.h index 5f68610e4d..a07e68dbed 100644 --- a/ports/samd/samd_soc.h +++ b/ports/samd/samd_soc.h @@ -29,18 +29,6 @@ #include #include "sam.h" -#if defined(MCU_SAMD21) - -#define CPU_FREQ (48000000) -#define USARTx SERCOM0 - -#elif defined(MCU_SAMD51) - -#define CPU_FREQ (48000000) -#define USARTx SERCOM3 - -#endif - void samd_init(void); void samd_main(void);