Revision: 1578
Author: jsuijs
Date: Fri Jan 1 10:35:40 2010
Log: Calibrated timing
http://code.google.com/p/jallib/source/detail?r=1578
Modified:
/trunk/include/peripheral/usart/serial_software.jal
=======================================
--- /trunk/include/peripheral/usart/serial_software.jal Wed Nov 4 14:19:03
2009
+++ /trunk/include/peripheral/usart/serial_software.jal Fri Jan 1 10:35:40
2010
@@ -81,70 +81,72 @@
--- receiving is optimized for 20 Mhz, 320_400 Baud
--- Number of instructions = (3 * olval * Ilval) + (4 * olval) + 15
--- 320kB ==> olval = ilval = 1
--- next optimization for 20 Mhz, 115_200 Baud olval = 1
--- olval = 1 ==> ilval = 8
--- all other buadrates downto 1200 shouldnt be a problem now
--- because of "IF-statement" this constant must be declared as a var
-
-var byte ilval
-var byte olval
-var byte ilval0
-
-if serial_sw_baudrate < 200_000 then
- const _olval = ( _NINSTR / ( 3 * 255 )) + 1
- const _ilval = ( ( _NINSTR - ( 4 * _olval ) ) - 15 ) / ( 3 * _olval )
- const _ilval0 = ( ( _NINSTR2 - ( 4 * _olval ) ) - 5 ) / ( 3 * _olval )
-
-
- ilval = _ilval
- olval = _olval
- ;due to rounding the next value can slightly below 1
- if _ilval0 > 0 then
- ilval0 = _ilval0
- else
- ilval0 = 1
- end if
- ilval0 = _ilval0
-
- -- test if baudrate valid for the chosen Xtal frequency
- if _olval > 255 then
- pragma error -- baudrate too low for this Xtal
- end if
- if _olval == 0 then
- pragma error -- baudrate too high for this Xtal
- end if
-
-else
- const _ilval = 1
- const _olval = ((target_clock / (4 * serial_sw_baudrate)) - 15 ) / (4 +
3 * _ilval)
- ilval = _ilval
- olval = _olval
-
-end if
-
--- For Xtal = 20_000_000, the following counter values are calculated (in
Hex)
--- Baud olcnt ilcnt ILcnt0 Ninstr
--- 110 3C FB 7C
--- 300 16 FA 7C
--- 600 0B FA 7C
--- 1200 06 E5 72
--- 2400 03 E4 72
--- 4800 02 A9 55
--- 9600 01 A7 55
--- 14_400 01 6D 38
--- 19_200 01 50 2A
--- 38_400 01 25 14
--- 57_600 01 16 0D
--- 115_200 01 08 05 43
--- 230_400 ? ? ? 22 NOT TESTED
---
--- Test sequence used (Hex)
--- 01 02 04 08 10 20 40 80 00 FF AA 55
-
-
+;-- receiving is optimized for 20 Mhz, 320_400 Baud
+;-- Number of instructions = (3 * olval * Ilval) + (4 * olval) + 15
+;-- 320kB ==> olval = ilval = 1
+;-- next optimization for 20 Mhz, 115_200 Baud olval = 1
+;-- olval = 1 ==> ilval = 8
+;-- all other buadrates downto 1200 shouldnt be a problem now
+;-- because of "IF-statement" this constant must be declared as a var
+;
+;var byte ilval
+;var byte olval
+;var byte ilval0
+;
+;if serial_sw_baudrate < 200_000 then
+; const _olval = ( _NINSTR / ( 3 * 255 )) + 1
+; const _ilval = ( ( _NINSTR - ( 4 * _olval ) ) - 15 ) / ( 3 * _olval )
+; const _ilval0 = ( ( _NINSTR2 - ( 4 * _olval ) ) - 5 ) / ( 3 * _olval )
+;
+;
+; ilval = _ilval
+; olval = _olval
+; ;due to rounding the next value can slightly below 1
+; if _ilval0 > 0 then
+; ilval0 = _ilval0
+; else
+; ilval0 = 1
+; end if
+; ilval0 = _ilval0
+;
+; -- test if baudrate valid for the chosen Xtal frequency
+; if _olval > 255 then
+; pragma error -- baudrate too low for this Xtal
+; end if
+; if _olval == 0 then
+; pragma error -- baudrate too high for this Xtal
+; end if
+;
+;else
+; const _ilval = 1
+; const _olval = ((target_clock / (4 * serial_sw_baudrate)) - 15 ) / (4
+ 3 * _ilval)
+; ilval = _ilval
+; olval = _olval
+;
+;end if
+;
+;-- For Xtal = 20_000_000, the following counter values are calculated (in
Hex)
+;-- Baud olcnt ilcnt ILcnt0 Ninstr
+;-- 110 3C FB 7C
+;-- 300 16 FA 7C
+;-- 600 0B FA 7C
+;-- 1200 06 E5 72
+;-- 2400 03 E4 72
+;-- 4800 02 A9 55
+;-- 9600 01 A7 55
+;-- 14_400 01 6D 38
+;-- 19_200 01 50 2A
+;-- 38_400 01 25 14
+;-- 57_600 01 16 0D
+;-- 115_200 01 08 05 43
+;-- 230_400 ? ? ? 22 NOT TESTED
+;--
+;-- Test sequence used (Hex)
+;-- 01 02 04 08 10 20 40 80 00 FF AA 55
+
+-- calculate instruction execution time in 10ns units
+const serial_sw_instruction_time = 400_000_000 / target_clock
+const serial_sw_bit_time = (1_000_000/serial_sw_baudrate) - ((13 *
serial_sw_instruction_time) / 100)
-- Waits untill a character is received.
-- Interrupts will be disabled during this routine, but restored
afterwards.
@@ -166,16 +168,16 @@
if serial_sw_invert then
serial_sw_tx_pin = low
- _usec_delay((1_000_000/serial_sw_baudrate)-2)
+ _usec_delay(serial_sw_bit_time)
for 8 loop
-- wait a whole bittime, less some usec for other actions
serial_sw_tx_pin = data_bit
data = data >> 1
- _usec_delay((1_000_000/serial_sw_baudrate)-2)
+ _usec_delay(serial_sw_bit_time)
end loop
-- add stop bit(s)
serial_sw_tx_pin = high
- _usec_delay((serial_sw_stopbits * (1_000_000/serial_sw_baudrate)))
+ _usec_delay(serial_sw_stopbits * serial_sw_bit_time)
else
-- invert the data
@@ -186,11 +188,11 @@
-- wait a whole bittime, less some usec for other actions
serial_sw_tx_pin = data_bit
data = data >> 1
- _usec_delay((1_000_000/serial_sw_baudrate)-2)
+ _usec_delay(serial_sw_bit_time)
end loop
-- add stop bit(s)
serial_sw_tx_pin = low
- _usec_delay((serial_sw_stopbits * (1_000_000/serial_sw_baudrate)))
+ _usec_delay(serial_sw_stopbits * serial_sw_bit_time)
end if
-- restore old interrupt status
@@ -226,14 +228,14 @@
while serial_sw_rx_pin loop end loop
-- wait half a bit time, less 5 usec for other actions
- _usec_delay((1_000_000/(2*serial_sw_baudrate))-1)
+ _usec_delay(serial_sw_bit_time / 2)
-- test if still startbit, otherwise restart
if !serial_sw_rx_pin then
-- now fetch 8 bits
for 8 loop
-- wait a whole bittime, less 5 usec for other actions
- _usec_delay((1_000_000/serial_sw_baudrate)-1)
+ _usec_delay(serial_sw_bit_time)
-- shift new bit in
data = data >> 1
if serial_sw_rx_pin then
@@ -255,14 +257,14 @@
while !serial_sw_rx_pin loop end loop
-- wait half a bit time, less 5 usec for other actions
- _usec_delay((1_000_000/(2*serial_sw_baudrate))-1)
+ _usec_delay((serial_sw_bit_time / 2)
-- test if still startbit, otherwise restart
if serial_sw_rx_pin then
-- now fetch 8 bits
for 8 loop
-- wait a whole bittime, less 5 usec for other actions
- _usec_delay((1_000_000/serial_sw_baudrate)-1)
+ _usec_delay((serial_sw_bit_time)
-- shift new bit in
data = data >> 1
if !serial_sw_rx_pin then
@@ -329,12 +331,12 @@
while serial_sw_rx_pin loop end loop
-- wait half a bit time, less 5 usec for other actions
- _usec_delay((1_000_000/(2*serial_sw_baudrate))-1)
+ _usec_delay(serial_sw_bit_time / 2)
-- now fetch 8 bits
for 8 loop
-- wait a whole bittime, less 5 usec for other actions
- _usec_delay((1_000_000/serial_sw_baudrate)-1)
+ _usec_delay(serial_sw_bit_time)
-- shift new bit in
data = data >> 1
if serial_sw_rx_pin then
@@ -346,12 +348,12 @@
while !serial_sw_rx_pin loop end loop
-- wait half a bit time, less 5 usec for other actions
- _usec_delay((1_000_000/(2*serial_sw_baudrate))-1)
+ _usec_delay(serial_sw_bit_time / 2)
-- now fetch 8 bits
for 8 loop
-- wait a whole bittime, less 5 usec for other actions
- _usec_delay((1_000_000/serial_sw_baudrate)-1)
+ _usec_delay((serial_sw_bit_time)
-- shift new bit in
data = data >> 1
if !serial_sw_rx_pin then
--
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