altos/cc1111: Document SPI bus pin options

Just a comment in the source code about which pins each option selects.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/cc1111/ao_spi.c b/src/cc1111/ao_spi.c
index 88cff9dd11815a7a02ef107c499959e6e927d6a2..52087fb4892dfd537e729cc8b65573a1baf37ba3 100644 (file)
--- a/src/cc1111/ao_spi.c
+++ b/src/cc1111/ao_spi.c
@@ -118,13 +118,34 @@ ao_spi_recv_bus(void __xdata *block, uint16_t len) __reentrant
 }
 
 /*
- * Initialize USART0 for SPI using config alt 2
+ * USART0 SPI config alt 2      (using this one)
  *
  *     MO      P1_5
  *     MI      P1_4
  *     CLK     P1_3
  *     CSS     P1_2
  *
+ * USART0 SPI config alt 1
+ * 
+ *     MO      P0_3
+ *     MI      P0_2
+ *     CLK     P0_5
+ *     SS      P0_4
+ *
+ * USART1 SPI config alt 2
+ *
+ *     MO      P1_6
+ *     MI      P1_7
+ *     CLK     P1_5
+ *     SS      P1_4
+ *
+ * USART1 SPI config alt 1
+ *
+ *     MO      P0_4
+ *     MI      P0_5
+ *     CLK     P0_3
+ *     SS      P0_2
+ *
  * Chip select is the responsibility of the caller in master mode
  */