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Merge pull request #6328 from KurtE/mixrt_uart_rs485

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[mimxrt (teensy) Allow Any GPIO pin for RS485 pin
This commit is contained in:
Dan Halbert 2022-05-04 13:30:09 -04:00 committed by GitHub
commit a7ec8b02e9
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 91 additions and 9 deletions
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88
ports/mimxrt10xx/common-hal/busio/UART.c
View File

@ -39,6 +39,17 @@
#include "periph.h"
#include "fsl_lpuart.h"
#include "fsl_gpio.h"
// ==========================================================
// Debug code
// ==========================================================
#define ENABLE_DEBUG_PRINTING 0
#if ENABLE_DEBUG_PRINTING
#define DBGPrintf mp_printf
#else
#define DBGPrintf(p,...)
#endif
// arrays use 0 based numbering: UART1 is stored at index 0
#define MAX_UART 8
@ -90,6 +101,7 @@ void common_hal_busio_uart_never_reset(busio_uart_obj_t *self) {
common_hal_never_reset_pin(self->rx);
common_hal_never_reset_pin(self->rts);
common_hal_never_reset_pin(self->cts);
common_hal_never_reset_pin(self->rs485_dir);
}
void common_hal_busio_uart_construct(busio_uart_obj_t *self,
@ -108,9 +120,12 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
mp_raise_ValueError(translate("Invalid word/bit length"));
}
DBGPrintf(&mp_plat_print, "uart_construct: tx:%p rx:%p rts:%p cts:%p rs485:%p\n", tx, rx, rts, cts, rs485_dir);
// We are transmitting one direction if one pin is NULL and the other isn't.
bool is_onedirection = (rx == NULL) != (tx == NULL);
bool uart_taken = false;
bool use_rts_for_rs485 = false;
const uint32_t rx_count = MP_ARRAY_SIZE(mcu_uart_rx_list);
const uint32_t tx_count = MP_ARRAY_SIZE(mcu_uart_tx_list);
@ -187,11 +202,14 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
// Filter for sane settings for RS485
if (rs485_dir != NULL) {
DBGPrintf(&mp_plat_print, "\t(485 pin): gpio:%p #:%x Mux: %x %x cfg:%x reset:%x %x\n",
rs485_dir->gpio, rs485_dir->number, rs485_dir->mux_idx, rs485_dir->mux_reg, rs485_dir->cfg_reg,
rs485_dir->mux_reset, rs485_dir->pad_reset);
if ((rts != NULL) || (cts != NULL)) {
mp_raise_ValueError(translate("Cannot specify RTS or CTS in RS485 mode"));
}
// For IMXRT the RTS pin is used for RS485 direction
rts = rs485_dir;
// For IMXRT the RTS pin is used for RS485 direction ???? - Can be will try
// it if this is an rts pin.
} else {
if (rs485_invert) {
mp_raise_ValueError(translate("RS485 inversion specified when not in RS485 mode"));
@ -202,16 +220,22 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
const uint32_t rts_count = MP_ARRAY_SIZE(mcu_uart_rts_list);
const uint32_t cts_count = MP_ARRAY_SIZE(mcu_uart_cts_list);
if (rts != NULL) {
if ((rts != NULL) || (rs485_dir != NULL)) {
for (uint32_t i = 0; i < rts_count; ++i) {
if (mcu_uart_rts_list[i].bank_idx == rx_config->bank_idx) {
if (mcu_uart_rts_list[i].pin == rts) {
rts_config = &mcu_uart_rts_list[i];
break;
} else if (mcu_uart_rts_list[i].pin == rs485_dir) {
rts_config = &mcu_uart_rts_list[i];
use_rts_for_rs485 = true;
rts = rs485_dir;
rs485_dir = NULL;
break;
}
}
}
if (rts_config == NULL) {
if ((rts != NULL) && (rts_config == NULL)) {
mp_raise_ValueError_varg(translate("Invalid %q pin"), MP_QSTR_RTS);
}
}
@ -225,7 +249,7 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
}
}
}
if (cts == NULL) {
if (cts_config == NULL) {
mp_raise_ValueError_varg(translate("Invalid %q pin"), MP_QSTR_CTS);
}
}
@ -257,7 +281,32 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
config_periph_pin(cts_config);
self->cts = cts;
}
if (rs485_dir) {
DBGPrintf(&mp_plat_print, "\tInit rs485 pin\n");
// lets configure this pin as standard GPIO output pin.
claim_pin(rs485_dir);
#define IOMUXC_SW_MUX_CTL_PAD_MUX_MODE_ALT5 5U
IOMUXC_SetPinMux(rs485_dir->mux_reg, IOMUXC_SW_MUX_CTL_PAD_MUX_MODE_ALT5, 0, 0, 0, 0);
DBGPrintf(&mp_plat_print, "\tAfter IOMUXC_SetPinMux\n");
IOMUXC_SetPinConfig(0, 0, 0, 0, rs485_dir->cfg_reg,
IOMUXC_SW_PAD_CTL_PAD_HYS(1)
| IOMUXC_SW_PAD_CTL_PAD_PUS(0)
| IOMUXC_SW_PAD_CTL_PAD_PUE(0)
| IOMUXC_SW_PAD_CTL_PAD_PKE(1)
| IOMUXC_SW_PAD_CTL_PAD_ODE(0)
| IOMUXC_SW_PAD_CTL_PAD_SPEED(2)
| IOMUXC_SW_PAD_CTL_PAD_DSE(1)
| IOMUXC_SW_PAD_CTL_PAD_SRE(0));
DBGPrintf(&mp_plat_print, "\tAfter IOMUXC_SetPinConfig\n");
const gpio_pin_config_t config = { kGPIO_DigitalOutput, rs485_invert, kGPIO_NoIntmode };
GPIO_PinInit(rs485_dir->gpio, rs485_dir->number, &config);
DBGPrintf(&mp_plat_print, "\tAfter GPIO_PinInit\n");
self->rs485_dir = rs485_dir;
self->rs485_invert = rs485_invert;
}
lpuart_config_t config = { 0 };
LPUART_GetDefaultConfig(&config);
@ -279,7 +328,7 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
// Before we init, setup RS485 direction pin
// ..unfortunately this isn't done by the driver library
uint32_t modir = (self->uart->MODIR) & ~(LPUART_MODIR_TXRTSPOL_MASK | LPUART_MODIR_TXRTSE_MASK);
if (rs485_dir != NULL) {
if (use_rts_for_rs485) {
modir |= LPUART_MODIR_TXRTSE_MASK;
if (rs485_invert) {
modir |= LPUART_MODIR_TXRTSPOL_MASK;
@ -311,6 +360,7 @@ void common_hal_busio_uart_construct(busio_uart_obj_t *self,
claim_pin(self->rx);
}
DBGPrintf(&mp_plat_print, "\t<< Init completed >>\n");
}
bool common_hal_busio_uart_deinited(busio_uart_obj_t *self) {
@ -330,9 +380,16 @@ void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {
common_hal_reset_pin(self->rx);
common_hal_reset_pin(self->tx);
common_hal_reset_pin(self->cts);
common_hal_reset_pin(self->rts);
common_hal_reset_pin(self->rs485_dir);
self->rx = NULL;
self->tx = NULL;
self->cts = NULL;
self->rts = NULL;
self->rs485_dir = NULL;
}
// Read characters.
@ -371,6 +428,10 @@ size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t
uint32_t recvd = 0;
LPUART_TransferGetReceiveCount(self->uart, &self->handle, &recvd);
LPUART_TransferAbortReceive(self->uart, &self->handle);
if (recvd == 0) {
*errcode = EAGAIN;
return MP_STREAM_ERROR;
}
return recvd;
}
@ -393,8 +454,21 @@ size_t common_hal_busio_uart_write(busio_uart_obj_t *self, const uint8_t *data,
if (self->tx == NULL) {
mp_raise_ValueError(translate("No TX pin"));
}
if (self->rs485_dir && len) {
GPIO_PinWrite(self->rs485_dir->gpio, self->rs485_dir->number, !self->rs485_invert);
LPUART_WriteBlocking(self->uart, data, len);
// Probably need to verify we have completed output.
uint32_t dont_hang_count = 0xffff;
while (dont_hang_count--) {
if (LPUART_GetStatusFlags(self->uart) & kLPUART_TransmissionCompleteFlag) {
break; // hardware says it completed.
}
}
GPIO_PinWrite(self->rs485_dir->gpio, self->rs485_dir->number, self->rs485_invert);
} else {
// could combine with above but would go through two ifs
LPUART_WriteBlocking(self->uart, data, len);
}
return len;
}

3
ports/mimxrt10xx/common-hal/busio/UART.h
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@ -50,6 +50,9 @@ typedef struct {
const mcu_pin_obj_t *tx;
const mcu_pin_obj_t *cts;
const mcu_pin_obj_t *rts;
const mcu_pin_obj_t *rs485_dir;
bool rs485_invert;
} busio_uart_obj_t;
void uart_reset(void);

7
shared-bindings/busio/UART.c
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@ -63,7 +63,12 @@
//| :param int receiver_buffer_size: the character length of the read buffer (0 to disable). (When a character is 9 bits the buffer will be 2 * receiver_buffer_size bytes.)
//|
//| *New in CircuitPython 4.0:* ``timeout`` has incompatibly changed units from milliseconds to seconds.
//| The new upper limit on ``timeout`` is meant to catch mistaken use of milliseconds."""
//| The new upper limit on ``timeout`` is meant to catch mistaken use of milliseconds.
//|
//| .. note:: RS485 support on i.MX and Raspberry Pi RP2040 is implemented in software.
//| The timing for the ``rs485_dir`` pin signal is done on a best-effort basis, and may not meet
//| RS485 specifications intermittently.
//| """
//| ...
//|
typedef struct {