From: ian <ian>
Date: Sun, 13 Nov 2005 01:58:46 +0000 (+0000)
Subject: i2clib inc
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=029dd9cf4af4921708f3450e48209aa89d3ddf81;p=trains.git

i2clib inc
---

diff --git a/detpic/i2clib.asm b/detpic/i2clib.asm
new file mode 100644
index 0000000..523e43b
--- /dev/null
+++ b/detpic/i2clib.asm
@@ -0,0 +1,92 @@
+;######################################################################
+; i2clib.inc - I2C LIBRARY - IMPLEMENTATION
+;
+; See i2clib.asm for documentation of the interface to this file.
+
+ include /usr/share/gputils/header/p18f458.inc
+ radix dec
+ include ../iwjpictest/insn-aliases.inc
+
+;============================================================
+; COMMON ADMINISTRATIVE ROUTINES
+
+		udata_acs
+t		res	1
+
+		code
+
+;--------------------
+i2cs_init
+;	W		slave number		undefined
+		rcall	slave2addr2
+		mov_wf	SSPADD
+		mov_lw	0x16 ; !SSPEN, CKP(release), I2C 7-bit slave
+		mov_wf	SSPCON1
+		mov_lw	0x81 ; GCEN, SEN
+		mov_wf	SSPCON2
+		mov_lw	0x8 ; SMP(noslew), !CKE, !BF(empty)
+		mov_wf	SSPSTAT
+		bs_f	TRISB, 0
+		bs_f	TRISB, 1
+		bc_f	IPR1, SSPIP
+		bs_f	SSPCON1, SSPEN
+		bs_f	PIE1, SSPIE
+		return
+
+;--------------------
+i2cs_interrupt
+		bt_f_if0 PIR1, SSPIF
+		return
+; We have an interrupt.  What are the possibilities ?
+		mov_ff	SSPSTAT, t
+
+chkval macro mask, value, label
+		mov_fw	t
+		and_lw	mask
+		xor_lw	value
+		bra_z	label
+		endm
+			; bits we want to check
+			;  80  60  20    04    02  01
+			;  SMP CKE D_A   R_W   UA  BF
+			;  set clr data? read? clr full?
+
+		chkval	0xe3, 0x81, got_addr
+		chkval	0xe7, 0xa1, got_data_write
+		chkval	0xe7, 0xa4, sent_data_read
+
+		
+
+		mov_fw	SSPSTAT
+		and_lw	0xe7 ; all except P and S
+
+		xor_lw	0x80
+			; bits which might sensibly be set
+
+chkval_last equ 0
+chkval macro value, label
+		xor_lw	value ^ chkval_last
+		bra_z	label
+chkval_last equ value
+		endm
+		chkval	0x80 ;     addr  dunno 
+
+		mov_lw	0x8
+
+
+		bt_f_if0 DATA_ADDRESS, SSPSTAT
+		bra	data
+
+slave2addr
+; computes slave address in form suitable for use in i2c controller
+; actual i2c slave address is (slave number) + 0b0001000
+;	W		slave number		i2c address * 2
+		add_lw	0b0001000
+		rlc_w
+		return
+
+
+
+
+ include i2clib.inc
+ end
diff --git a/detpic/i2clib.inc b/detpic/i2clib.inc
index 5392468..8195fbd 100644
--- a/detpic/i2clib.inc
+++ b/detpic/i2clib.inc
@@ -1,5 +1,5 @@
 ;######################################################################
-; i2clib.inc - I2C LIBRARY, DECLARATIONS AND DOCUMENTATION
+; i2clib.inc - I2C LIBRARY - DECLARATIONS AND DOCUMENTATION
 ;
 ;
 ;============================================================
@@ -81,6 +81,7 @@ extern i2cs_init
 ;   State			Not-in-use		Idle
 ;   W				slave number		any
 
+;--------------------
 extern i2cs_interrupt
 extern i2cm_interrupt
 ;