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authorJared Boone2012-06-15 17:20:50 -0700
committerJared Boone2012-06-15 17:20:50 -0700
commit536c92257755487710088df6ac4932ea25005e3e (patch)
tree3e12ef071320a338de93e390628f248a996ef2ff
parente28d07b81efd8eb3bccc01505d7c3aa5c2b09f45 (diff)
Modified SSP driver to wait for data to be sent before returning. This is critical when controlling device CS# pins via GPIO. Long-term, it might be better to have a different API that permits this level of control.
-rw-r--r--lib/lpc43xx/ssp.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/lib/lpc43xx/ssp.c b/lib/lpc43xx/ssp.c
index 592b5d8..e9cf5b0 100644
--- a/lib/lpc43xx/ssp.c
+++ b/lib/lpc43xx/ssp.c
@@ -113,6 +113,21 @@ u16 ssp_read(ssp_num_t ssp_num)
return SSP_DR(ssp_port);
}
+void ssp_wait_until_not_busy(ssp_num_t ssp_num)
+{
+ u32 ssp_port;
+
+ if(ssp_num == SSP0_NUM)
+ {
+ ssp_port = SSP0;
+ }else
+ {
+ ssp_port = SSP1;
+ }
+
+ while( (SSP_SR(ssp_port) & SSP_SR_BSY) );
+}
+
/* This Function Wait Data TX Ready, and Write Data to SSP */
void ssp_write(ssp_num_t ssp_num, u16 data)
{
@@ -130,5 +145,16 @@ void ssp_write(ssp_num_t ssp_num, u16 data)
while( (SSP_SR(ssp_port) & SSP_SR_TNF) == 0);
SSP_DR(ssp_port) = data;
+
+ /* Wait for not busy, since we're controlling CS# of
+ * devices manually and need to wait for the data to
+ * be sent. It may also be important to wait here
+ * in case we're configuring devices via SPI and also
+ * with GPIO control -- we need to know when SPI
+ * commands are effective before altering a device's
+ * state with GPIO. I'm thinking the MAX2837, for
+ * example...
+ */
+ ssp_wait_until_not_busy(ssp_num);
}