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Correction of baudrate calculation for QUICC SMC uart
- From: "Tord Andersson" <Tord dot Andersson at combitechsystems dot com>
- To: <ecos-discuss at sources dot redhat dot com>
- Date: Mon, 8 Sep 2003 08:58:10 +0200
- Subject: [ECOS] Correction of baudrate calculation for QUICC SMC uart
Hi,
When using higher baudrates in an MPC823e based system using eCos and
the SMC UART, I found that the baudrate was slightly wrong. I checked
the baudrate calculation and believe that it could be somewhat altered.
The change has solved our problem.
Below is the result of "diff -u -5 -b -p" between the original and the
patched file for review.
The file is located in
.../packages/devs/serial/powerpc/quicc/current/src
---------------------------------------
--- quicc_smc_serial.h Thu Sep 4 08:50:14 2003
+++ patched_quicc_smc_serial.h Thu Sep 4 09:04:26 2003
@@ -130,8 +130,8 @@
0, // 230400
};
-#define UART_BITRATE(n)
(((CYGHWR_HAL_POWERPC_BOARD_SPEED*1000000)/16)/n)
-#define UART_SLOW_BITRATE(n)
((CYGHWR_HAL_POWERPC_BOARD_SPEED*1000000)/n))
+#define UART_BITRATE(n)
((((CYGHWR_HAL_POWERPC_BOARD_SPEED*1000000)/16)/n)-1)
+#define UART_SLOW_BITRATE(n)
(((CYGHWR_HAL_POWERPC_BOARD_SPEED*1000000)/n))-1)
// Channel type select
#define _SCC_CHAN 0
--------------------------------------
Kind regards,
Tord Andersson
Combitech Systems AB
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