From: Nathael Pajani <nathael.pajani@ed3l.fr>
Date: Fri, 13 Dec 2013 10:18:58 +0000 (+0100)
Subject: Export spi_transfer_single_frame() to "user" (code) space
X-Git-Url: http://git.techno-innov.fr/?a=commitdiff_plain;h=de566c0ef3355d71fce43e638fcb8790119d41bf;p=soft%2Flpc122x%2Fcore

Export spi_transfer_single_frame() to "user" (code) space
---

diff --git a/drivers/ssp.c b/drivers/ssp.c
index 574f6d2..d4dd498 100644
--- a/drivers/ssp.c
+++ b/drivers/ssp.c
@@ -114,7 +114,7 @@ uint16_t spi_transfer_single_frame(uint16_t data)
 	struct lpc_ssp* ssp = LPC_SSP0;
 	ssp->data = data;
 	/* Wait until the busy bit is cleared */
-	do {} while (ssp->status & LPC_SSP_ST_BUSY);
+	while (ssp->status & LPC_SSP_ST_BUSY);
 	return ssp->data;
 }
 
diff --git a/include/drivers/ssp.h b/include/drivers/ssp.h
index cfc7e2e..a46463a 100644
--- a/include/drivers/ssp.h
+++ b/include/drivers/ssp.h
@@ -37,6 +37,18 @@
 void spi_cs_pull_low(void);
 void spi_cs_release(void);
 
+
+/***************************************************************************** */
+/* This function is used to transfer a byte to AND from a device
+ * As the SPI bus is full duplex, data can flow in both directions, but the clock is
+ *   always provided by the master. The SPI clock cannont be activated without sending
+ *   data, which means we must send data to the device when we want to read data from
+ *   the device.
+ * This function does not take care of the SPI chip select.
+ */
+uint16_t spi_transfer_single_frame(uint16_t data);
+
+
 /***************************************************************************** */
 /* Write data to the SPI bus.
  * Any data received while sending is discarded.