Revision: 1689
Author: jsuijs
Date: Sat Feb 20 13:29:44 2010
Log: support for 16-bit baudrate register
http://code.google.com/p/jallib/source/detail?r=1689
Modified:
/trunk/include/peripheral/usart/usart_common.jal
=======================================
--- /trunk/include/peripheral/usart/usart_common.jal Tue Jan 27 02:09:39
2009
+++ /trunk/include/peripheral/usart/usart_common.jal Sat Feb 20 13:29:44
2010
@@ -1,5 +1,5 @@
-- Title: USART common
--- Author: Stef Mientki Copyright (c) 2002..2006, all rights reserved.
+-- Author: Stef Mientki Copyright (c) 2002..2010, all rights reserved.
-- Adapted-by: Sebastien Lelong, Joep Suijs
-- Compiler: >=2.4g
--
@@ -42,24 +42,14 @@
procedure _calculate_and_set_baudrate() is
const max_deviation = 5 -- maximum % deviation of the realized baudrate
- if usart_hw_serial then
- -- SPBRG = ( Fosc / ( 4 * Baudrate ) ) -1
- -- first try high baudrate, will generate highest accuarcy
- -- to get the right rounding (5 + 10*f(x)) /10
- const usart_div =((5 + ( ( 10 * target_clock ) / ( 16 *
serial_hw_baudrate )) ) / 10 ) - 1
-
- -- special case if divider is 0,
- -- test if deviation is not too much
- if usart_div <= 0 then
- if (100 * (serial_hw_baudrate - (target_clock / 16) )) /
serial_hw_baudrate >= max_deviation then
- pragma error -- asynchronous baudrate is too high
- end if
- end if
-
- -- if divider small enough,
- -- calculate divider and set high-speed
- const real_baud = target_clock / 16 / (usart_div + 1)
- if usart_div <= 255 then
+ if usart_hw_serial then
+ if (defined(BAUDCTL_BRG16) == true) then
+ BAUDCTL_BRG16 = true
+ TXSTA_BRGH = true
+
+ const usart_div =((5 + ( ( 10 * target_clock ) / ( 4 *
serial_hw_baudrate )) ) / 10 ) - 1
+ const real_baud = target_clock / 4 / ((usart_div & 0xffff) + 1)
+
if (real_baud > serial_hw_baudrate) then
if (100 * (real_baud - serial_hw_baudrate) /
serial_hw_baudrate >= max_deviation) then
pragma error -- asynchronous baudrate deviation is too
large
@@ -70,13 +60,45 @@
end if
end if
- if usart_div >= 0 then
- SPBRG = usart_div
- else
- SPBRG = 0
+ SPBRG = byte(usart_div)
+ SPBRGH = byte(usart_div >> 8)
+
+ else
+ -- SPBRG = ( Fosc / ( 4 * Baudrate ) ) -1
+ -- first try high baudrate, will generate highest accuarcy
+ -- to get the right rounding (5 + 10*f(x)) /10
+ const usart_div =((5 + ( ( 10 * target_clock ) / ( 16 *
serial_hw_baudrate )) ) / 10 ) - 1
+
+ -- special case if divider is 0,
+ -- test if deviation is not too much
+ if usart_div <= 0 then
+ if (100 * (serial_hw_baudrate - (target_clock / 16) )) /
serial_hw_baudrate >= max_deviation then
+ pragma error -- asynchronous baudrate is too high
+ end if
end if
- TXSTA_BRGH = true
- -- try the low-speed mode
+
+ -- if divider small enough,
+ -- calculate divider and set high-speed
+ const real_baud = target_clock / 16 / (usart_div + 1)
+ if usart_div <= 255 then
+ if (real_baud > serial_hw_baudrate) then
+ if (100 * (real_baud - serial_hw_baudrate) /
serial_hw_baudrate >= max_deviation) then
+ pragma error -- asynchronous baudrate deviation is too
large
+ end if
+ else
+ if (100 * (serial_hw_baudrate - real_baud) /
serial_hw_baudrate >= max_deviation) then
+ pragma error -- asynchronous baudrate deviation is too
large
+ end if
+ end if
+
+ if usart_div >= 0 then
+ SPBRG = usart_div
+ else
+ SPBRG = 0
+ end if
+ TXSTA_BRGH = true
+ -- try the low-speed mode
+ end if
else
const usart_div_low = ((((10 * target_clock) / ( 64 *
serial_hw_baudrate )) + 5 ) / 10) - 1
-- here divider will never be 0
--
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