- sped up transfer(buf, rxbuf, count) a little by making it use direct byte transfers and not calling transfer(data)

RudolphRiedel · RudolphRiedel · commit 2d0bedc701eb · 2023-07-11T15:58:47.000+02:00
diff --git a/libraries/SPI/SPI.cpp b/libraries/SPI/SPI.cpp
@@ -386,7 +386,9 @@ void ArduinoSPI::transfer(void *buf, void *rxbuf, size_t count)
             uint8_t *rx = (uint8_t *) rxbuf;
             const uint8_t* tx = (const uint8_t *) buf;
             for (size_t i = 4U * n32; i < count; i++) {
-                uint8_t tmp = transfer((buf) ? tx[i] : 0xFF);
+                _spi_ctrl.p_regs->SPDR_BY = (buf) ? tx[i] : 0xFF;
+                while (0U == _spi_ctrl.p_regs->SPSR_b.SPRF) {}
+                uint8_t tmp = _spi_ctrl.p_regs->SPDR_BY;
                 if (rxbuf) {
                     rx[i] = tmp;
                 }
@@ -395,7 +397,6 @@ void ArduinoSPI::transfer(void *buf, void *rxbuf, size_t count)
     }
 }
 
-
 void ArduinoSPI::beginTransaction(arduino::SPISettings settings)
 {
   if (!_is_initialized)

Original file line number	Diff line number	Diff line change
`@@ -386,7 +386,9 @@ void ArduinoSPI::transfer(void buf, void rxbuf, size_t count)`
`386`	`386`	`uint8_t rx = (uint8_t ) rxbuf;`
`387`	`387`	`const uint8_t* tx = (const uint8_t *) buf;`
`388`	`388`	`for (size_t i = 4U * n32; i < count; i++) {`
`389`		`- uint8_t tmp = transfer((buf) ? tx[i] : 0xFF);`
	`389`	`+ _spi_ctrl.p_regs->SPDR_BY = (buf) ? tx[i] : 0xFF;`
	`390`	`+ while (0U == _spi_ctrl.p_regs->SPSR_b.SPRF) {}`
	`391`	`+ uint8_t tmp = _spi_ctrl.p_regs->SPDR_BY;`
`390`	`392`	`if (rxbuf) {`
`391`	`393`	`rx[i] = tmp;`
`392`	`394`	`}`
`@@ -395,7 +397,6 @@ void ArduinoSPI::transfer(void buf, void rxbuf, size_t count)`
`395`	`397`	`}`
`396`	`398`	`}`
`397`	`399`
`398`		`-`
`399`	`400`	`void ArduinoSPI::beginTransaction(arduino::SPISettings settings)`
`400`	`401`	`{`
`401`	`402`	`if (!_is_initialized)`