From 7fc402f3b5a6f0d320959b86d5a18c425cbc0b3f Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@bcmi-labs.cc>
Date: Thu, 31 Aug 2017 14:09:09 -0400
Subject: [PATCH] Leverage SERCOM h/w functionality for RTS and CTS
---
cores/arduino/SERCOM.cpp | 10 ++++++++++
cores/arduino/SERCOM.h | 2 ++
cores/arduino/Uart.cpp | 41 ++++++++++++++++++++--------------------
3 files changed, 32 insertions(+), 21 deletions(-)
diff --git a/cores/arduino/SERCOM.cpp b/cores/arduino/SERCOM.cpp
index 42c46d01..d0f50a6b 100644
--- a/cores/arduino/SERCOM.cpp
+++ b/cores/arduino/SERCOM.cpp
@@ -183,6 +183,16 @@ void SERCOM::disableDataRegisterEmptyInterruptUART()
sercom->USART.INTENCLR.reg = SERCOM_USART_INTENCLR_DRE;
}
+void SERCOM::enableReceiveCompleteInterruptUART()
+{
+ sercom->USART.INTENSET.reg |= SERCOM_USART_INTENSET_RXC;
+}
+
+void SERCOM::disableReceiveCompleteInterruptUART()
+{
+ sercom->USART.INTENCLR.reg = SERCOM_USART_INTENCLR_RXC;
+}
+
/* =========================
* ===== Sercom SPI
* =========================
diff --git a/cores/arduino/SERCOM.h b/cores/arduino/SERCOM.h
index 6b7c703a..77609f87 100644
--- a/cores/arduino/SERCOM.h
+++ b/cores/arduino/SERCOM.h
@@ -165,6 +165,8 @@ class SERCOM
void acknowledgeUARTError() ;
void enableDataRegisterEmptyInterruptUART();
void disableDataRegisterEmptyInterruptUART();
+ void enableReceiveCompleteInterruptUART();
+ void disableReceiveCompleteInterruptUART();
/* ========== SPI ========== */
void initSPI(SercomSpiTXPad mosi, SercomRXPad miso, SercomSpiCharSize charSize, SercomDataOrder dataOrder) ;
diff --git a/cores/arduino/Uart.cpp b/cores/arduino/Uart.cpp
index 6ef5338f..2b54787f 100644
--- a/cores/arduino/Uart.cpp
+++ b/cores/arduino/Uart.cpp
@@ -46,12 +46,11 @@ void Uart::begin(unsigned long baudrate, uint16_t config)
pinPeripheral(uc_pinTX, g_APinDescription[uc_pinTX].ulPinType);
if (uc_pinRTS != NO_RTS_PIN) {
- pinMode(uc_pinRTS, OUTPUT);
- digitalWrite(uc_pinRTS, LOW);
+ pinPeripheral(uc_pinRTS, g_APinDescription[uc_pinRTS].ulPinType);
}
if (uc_pinCTS != NO_CTS_PIN) {
- pinMode(uc_pinCTS, INPUT);
+ pinPeripheral(uc_pinCTS, g_APinDescription[uc_pinCTS].ulPinType);
}
sercom->initUART(UART_INT_CLOCK, SAMPLE_RATE_x16, baudrate);
@@ -86,9 +85,10 @@ void Uart::IrqHandler()
rxBuffer.store_char(sercom->readDataUART());
if (uc_pinRTS != NO_RTS_PIN) {
- // if there is NOT enough space in the RX buffer, de-assert RTS
+ // if there is NOT enough space in the RX buffer,
+ // diable the receive complete interrupt
if (rxBuffer.availableForStore() < RTS_RX_THRESHOLD) {
- digitalWrite(uc_pinRTS, HIGH);
+ sercom->disableReceiveCompleteInterruptUART();
}
}
}
@@ -132,9 +132,10 @@ int Uart::read()
int c = rxBuffer.read_char();
if (uc_pinRTS != NO_RTS_PIN) {
- // if there is enough space in the RX buffer, assert RTS
+ // if there is enough space in the RX buffer,
+ // enable the receive completer interrupt
if (rxBuffer.availableForStore() > RTS_RX_THRESHOLD) {
- digitalWrite(uc_pinRTS, LOW);
+ sercom->enableReceiveCompleteInterruptUART();
}
}
@@ -143,16 +144,6 @@ int Uart::read()
size_t Uart::write(const uint8_t data)
{
- if (uc_pinRTS != NO_RTS_PIN) {
- // assert RTS
- digitalWrite(uc_pinRTS, LOW);
- }
-
- if (uc_pinCTS != NO_CTS_PIN) {
- // wait until CTS is asserted
- while (digitalRead(uc_pinCTS) != LOW);
- }
-
if (sercom->isDataRegisterEmptyUART() && txBuffer.available() == 0) {
sercom->writeDataUART(data);
} else {
@@ -217,14 +208,22 @@ SercomParityMode Uart::extractParity(uint16_t config)
int Uart::attachRts(uint8_t pin)
{
- uc_pinRTS = pin;
+ if (uc_padTX == UART_TX_RTS_CTS_PAD_0_2_3) {
+ uc_pinRTS = pin;
- return 1;
+ return 1;
+ }
+
+ return 0;
}
int Uart::attachCts(uint8_t pin)
{
- uc_pinCTS = pin;
+ if (uc_padTX == UART_TX_RTS_CTS_PAD_0_2_3) {
+ uc_pinCTS = pin;
- return 1;
+ return 1;
+ }
+
+ return 0;
}
--
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