; ====================== I2C2scsn.asm ==================
;
; I2C master
; by V.Angelov -- last modified: 15:57 / 23-Jun-2005
;
; Only one CPU is required, CPU0
;
; Typical usage:
;
; 1) initialize the srv_command with 0 and call the program
;    This will initialize the I2C interface
;
; 2) put in srv_command
; Bits 23..16          15..8           7..1            0
;      number_of_bytes start_address   device_address  read(1)/write(0)
;
; if number_of_bytes=0 the I2C will be initialized only
;
; 3) in case of writing store the bytes to be send starting
;    from srv_indata, one byte / address. This is not optimal, can be
;    3-4 bytes / address.
;
; 4) call the program
;
; 5) in case of reading the read bytes are from address
;    srv_outdata, one byte / address. Again, this can be optimized.
;
; If the I2C communication fails, the timeout counter will be incremented.
; It can be read at IO address srv_command.
;
; ======================================================

tst:
#ifdef traceon
        mvpcr 0, deb_reg
        sra+ deb_reg
#endif
        mov 0xFF, wrk
        iext srv_command
        lgio 0, srv_command
        jmpr cc_busy, 0
        lpio 0x300, r8
        and wrk, r8, dev_addr       ; -- device address
        shl -8, r8, ibit
        and wrk, ibit, start_addr   ; -- start address
        shl -8, ibit, ibit
        and wrk, ibit, nbytes       ; -- number of bytes
        jmp cc_zero, i2c_only_init
        shl -8, ibit, ibit
        andt dev_addr, c1           ; -- 1 for read, 0 for write
        mov  i2c_lp, return1        ; -- mov doesn't change the zero flag!
        jmp cc_zero,   i2c_swrite
        jmp cc_uncond, i2c_sread

i2c_only_init:
        mvpcr +2, return1
        jmp cc_uncond, i2c_init

i2c_lp:
#ifdef traceon
        mov 0xFFF, deb_reg
        sra+ deb_reg
#endif
        jmpr cc_busy, 0
        iext srv_command
        sgio timeoutcnt, srv_command
        jmpr cc_busy, 0
        mov  CMD_LP, dev_addr
        sgio dev_addr, SMCMD
        jmpr cc_uncond, 0
; END OF THE MAIN PROGRAM