;
; [Not-in-use]
; |
-; |init
-; v
+; |init
+; v
; [Idle]<-------------------------.
; write_begin/ \ |
; / \read_begin |
; Beforehand At call On return
; State Transmitting Idle
+;======================================================================
+; MASTER
+;
+; States:
+; [Not-in-use]
+; |
+; |init
+; v
+; [Idle]<-----------------------------.
+; write_start/ \ |
+; / \ |
+; V V |
+; [Writing-Setup] [Reading-Busy]<---------. |
+; | | | |
+; write_next_byte| |read_got_byte | |
+; must return NZ | | | |
+; V V | |
+; ,-->[Writing] [Reading-Wait] | |
+; `-------' \ / `-------------' |
+; write_next_byte \ / read_another |
+; returns NZ | / |
+; | /read_done |
+; write_next_byte| | |
+; returns Z | | |
+; V V |
+; [Stopping] |
+; | done |
+; `----------------------------------'
+
+;--------------------
+extern i2cmu_done
+
+; Called to notify that the previous conversation with the slave has
+; been finished as requested. The i2c system is now available and
+; i2cm_*_start can be called.
+;
+; Beforehand At call
+; State Stopping Idle
+
+;========================================
+; MASTER - WRITES (ie, transmission of data to the slave)
+
+;--------------------
+extern i2cm_write_start
+;
+; Requests that a slave be contacted for writing. When communication
+; has been established, i2cmu_write_next_byte will be called.
+;
+; At call On return
+; State Idle Writing-Setup
+; W slave number any
+
+extern i2cmu_write_next_byte
+;
+; Called to notify the main program that we are now ready to transmit
+; a byte to the slave that we're currently talking to. This may be
+; either because i2cm_write_start was previously called and
+; communication has been established, or because tranmission of the
+; previous byte is complete.
+;
+; The main program must immediately supply the actual data byte. This
+; byte will then be transmitted to the slave, and then
+; i2cmu_write_next_byte will be called again.
+; Alternatively the main program may indicate that the tranmission
+; should finish by setting the Z flag on return. In this case the
+; slave will be told that this is the end of the message and the i2c
+; conversation will be finished. When the conversation is finished
+; and the bus and i2c controller are free again, i2cmu_done will be
+; called.
+;
+; When transmission should continue:
+;
+; Beforehand At call On return After return
+; State Writing[-Setup] Writing Writing Writing
+; Status Z any 0 (NZ, not zero, not equal)
+; W any data for slave
+;
+; When transmission should finish:
+;
+; Beforehand At call On return After return
+; State Writing Writing Writing Stopping
+; Status Z any 1 (Z, zero, equal)
+; W any any
+;========================================
+; MASTER - READS (ie, reception of data from the slave)
+;--------------------
+extern i2cm_read_start
+;
+; Requests that a slave be contacted for reading. When communication
+; has been established and the first byte received,
+; i2cmu_read_got_byte will be called.
+;
+; At call On return
+; State Idle Reading-Busy
+; W slave number any
-; junky bits after here need turning into MASTER sections.
+extern i2cmu_read_got_byte
+;
+; Called to notify the main program that a byte has been recieved from
+; the slave PIC. The byte value is supplied. Communication with the
+; slave will be suspended (with the i2c bus blocked) until the main
+; program calls i2cm_read_another or i2cm_read_done. The main program
+; must call one of these two before doing anything else with the i2c.
+;
+; Beforehand At call
+; State Reading Reading-Wait
+; W data from slave
+extern i2cm_read_another
+;
+; Requests that the communication with the slave continue and another
+; byte be read. When this is complete, i2cmu_read_got_byte will be
+; called.
+;
+; At call On return
+; State Reading-Wait Reading-Busy
+extern i2cm_read_done
;
-; i2cm_write_start
-; slave no.
-; causes
-; i2cmu_write_next_byte
-; must return byte to transmit
-; must say whether to stop
-; stop causes
-; i2cmu_done
+; Requests that reading from the slave be terminated. When the
+; conversation is finished and the bus and i2c controller are free
+; again, i2cmu_done will be called.
;
-; i2cm_read_start
-; slave no.
-; causes
-; i2cmu_read_got_byte
-; byte value
-; causes
-; i2cm_read_another or i2cm_read_done
-; causes causes
-; i2cmu_done i2cmu_done
+; At call On return
+; State Reading-Wait Stopping
~ijackson / trains.git / commitdiff