Author: sebastien.lelong
Date: Wed Jan 21 12:51:42 2009
New Revision: 740
Modified:
trunk/include/peripheral/i2c/i2c_hw_slave_isr.jal
Log:
simplified calls
Modified: trunk/include/peripheral/i2c/i2c_hw_slave_isr.jal
==============================================================================
--- trunk/include/peripheral/i2c/i2c_hw_slave_isr.jal (original)
+++ trunk/include/peripheral/i2c/i2c_hw_slave_isr.jal Wed Jan 21 12:51:42
2009
@@ -49,112 +49,78 @@
--- state 1: write operation, last byte is address, buffer full
--- byte is an address, it we get here, we just know master
--- wants to talk to us, in a new write operation...
--- and we also know address is recognized (BF is set, see spec)
--- anyway, we must read buffer to reset BF bit
--- (buffer actually contains previously detected address, that's
--- why it's usually ignored)
---
--- => call i2c_hw_slave_on_state_1(byte)
-procedure i2c_hw_slave_proceed_state_1() is
- pragma inline
- var byte _trash = i2c_hw_slave_read_i2c()
- i2c_hw_slave_on_state_1(_trash)
-end procedure
-
--- state 2: write operation, last byte is data, buffer full
--- master wants to write, it sends a byte
---
--- => call i2c_hw_slave_on_state_2(byte)
-procedure i2c_hw_slave_proceed_state_2() is
- pragma inline
- var byte rcv = i2c_hw_slave_read_i2c()
- i2c_hw_slave_on_state_2(rcv)
-end procedure
-
-
--- state 3: read operation, last byte is address, buffer empty
--- master wants to get a value from us
---
--- => call i2c_hw_slave_on_state_3()
-procedure i2c_hw_slave_proceed_state_3() is
- pragma inline
- i2c_hw_slave_on_state_3()
-end procedure
-
-
--- state 4: read operation, last byte is data, buffer empty
--- master still wants to get a value from us
---
--- => call i2c_hw_slave_on_state_4()
-procedure i2c_hw_slave_proceed_state_4() is
- pragma inline
- i2c_hw_slave_on_state_4()
-end procedure
-
-
--- state 5: nack
--- master doesn't want to talk with us anymore
---
--- => call i2c_hw_slave_on_state_5()
-procedure i2c_hw_slave_proceed_state_5() is
- pragma inline
- -- AN734 does not talk about setting CKP, whereas spec says
- -- it must be set. Some people say it can be error prone.
- SSPCON1_CKP = 1
- i2c_hw_slave_on_state_5()
-end procedure
-
-
--- state not recognized... Error !
---
--- => call i2c_hw_slave_on_error()
-procedure i2c_hw_slave_proceed_error() is
- pragma inline
- -- something went wrong, that is, XOR operations did not match
- -- SSPSTAT bits
- i2c_hw_slave_on_error()
-end procedure
+
-- i2c ISR handler. Detects states a call appropriate procedures
procedure i2c_hw_slave_isr_handler() is
- pragma interrupt
- if ! PIR1_SSPIF then
- return
- end if
+ pragma interrupt
+ if ! PIR1_SSPIF then
+ return
+ end if
- PIR1_SSPIF = false
+ PIR1_SSPIF = false
var byte tmpstat
- tmpstat = SSPSTAT
- -- mask out unimportant bit
- tmpstat = tmpstat & 0b_0010_1101
- -- check state 1: write operation, last byte is address, buffer full
- if (tmpstat ^ 0b_0000_1001) == false
- then
- i2c_hw_slave_proceed_state_1()
- -- check state 2: write operation, last byte is data, buffer full
- elsif (tmpstat ^ 0b_0010_1001) == false
- then
- i2c_hw_slave_proceed_state_2()
- -- check state 3: read operation, last byte is address, buffer empty
- elsif (tmpstat ^ 0b_0000_1100) == false
- then
- i2c_hw_slave_proceed_state_3()
- -- check state 4: read operation, last byte is data, buffer empty
- elsif (tmpstat ^ 0b_00101100) == false
- then
- i2c_hw_slave_proceed_state_4()
- -- check state 5: nack
- elsif (tmpstat ^ 0b_0010_1000) == false
- then
- i2c_hw_slave_proceed_state_5()
- -- check only got a start signal (when using interrupts)
- else
- i2c_hw_slave_proceed_error()
- end if
+ tmpstat = SSPSTAT
+ -- mask out unimportant bit
+ tmpstat = tmpstat & 0b_0010_1101
+
+ -- state 1: write operation, last byte is address, buffer full
+ -- byte is an address, it we get here, we just know master
+ -- wants to talk to us, in a new write operation...
+ -- and we also know address is recognized (BF is set, see spec)
+ -- anyway, we must read buffer to reset BF bit
+ -- (buffer actually contains previously detected address, that's
+ -- why it's usually ignored)
+ --
+ -- => call i2c_hw_slave_on_state_1(byte)
+ if (tmpstat ^ 0b_0000_1001) == false
+ then
+ var byte _trash = i2c_hw_slave_read_i2c()
+ i2c_hw_slave_on_state_1(_trash)
+
+ -- state 2: write operation, last byte is data, buffer full
+ -- master wants to write, it sends a byte
+ --
+ -- => call i2c_hw_slave_on_state_2(byte)
+ elsif (tmpstat ^ 0b_0010_1001) == false
+ then
+ var byte rcv = i2c_hw_slave_read_i2c()
+ i2c_hw_slave_on_state_2(rcv)
+
+ -- state 3: read operation, last byte is address, buffer empty
+ -- master wants to get a value from us
+ --
+ -- => call i2c_hw_slave_on_state_3()
+ elsif (tmpstat ^ 0b_0000_1100) == false
+ then
+ i2c_hw_slave_on_state_3()
+
+ -- state 4: read operation, last byte is data, buffer empty
+ -- master still wants to get a value from us
+ --
+ -- => call i2c_hw_slave_on_state_4()
+ elsif (tmpstat ^ 0b_00101100) == false
+ then
+ i2c_hw_slave_on_state_4()
+
+ -- state 5: nack
+ -- master doesn't want to talk with us anymore
+ --
+ -- => call i2c_hw_slave_on_state_5()
+ elsif (tmpstat ^ 0b_0010_1000) == false
+ then
+ -- AN734 does not talk about setting CKP, whereas spec says
+ -- it must be set. Some people say it can be error prone.
+ SSPCON1_CKP = 1
+ i2c_hw_slave_on_state_5()
+
+ -- state not recognized... Error !
+ else
+ -- something went wrong, that is, XOR operations did not match
+ -- SSPSTAT bits
+ i2c_hw_slave_on_error()
+ end if
end procedure
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