'{$STAMP BS2p}
'{$PBASIC 2.5}
'Program description
'use 2 MAX7300 modules to address a DS1248 static ram (128K x 8)
'for write/read test

'*******I2C pin numbers ****************************************
SDA             PIN     0      'I2C serial data line
SCL             PIN     1      'I2C serial clock line

'******* MAX7300 module addresses ******************************
SlvAddr1        CON     $80
SlvAddr2        CON     $82

'******* Constants *********************************************
Config_addr     CON     $04     'addresses for 7300 ports
Port_config_Adr CON     $09
P_Cfg_12_15     CON     $0B
P_Cfg_16_19     CON     $0C
P_Cfg_20_23     CON     $0D
P_Cfg_24_27     CON     $0E
P_Cfg_28_31     CON     $0F

Ports_12_19     CON     $4C
Port_20         CON     $34
Ports_20_27     CON     $54
Port_28         CON     $3C
Ports_29_31     CON     $5D

'******* Varables *********************************************
I2Cdata         VAR     Byte
Wrt_data        VAR     Byte
RAM_Addr        VAR     Word
RAM_addr0       VAR     RAM_Addr.BYTE0
RAM_addr1       VAR     RAM_Addr.BYTE1
RAM_addr2       VAR     Nib

Init_7300:       'initialize MAX7300 and data/addr
    I2COUT sda,SlvAddr1,Config_Addr,[$01]    'take 7300's out of shutdown mode'    I2COUT sda,SlvAddr2,Config_Addr,[$01]
    I2COUT sda,SlvAddr2,Config_Addr,[$01]
    I2COUT sda,SlvAddr1,Port_config_adr,[REP %01010101\7] 'make all lines outputs
    I2COUT sda,SlvAddr2,Port_config_adr,[REP %01010101\7]
    I2COUT sda,SlvAddr2,Ports_29_31,[$7]    'set control lines high (CE,WE,OE )
    Wrt_data = $01
    RAM_addr0 = $01

Main:         'write to RAM
   I2COUT sda,SlvAddr2,P_Cfg_12_15, [REP %01010101\2]  'make data lines outputs
   I2COUT sda,Slvaddr1,Ports_12_19, [RAM_addr0,RAM_Addr1,RAM_Addr2]
   I2COUT sda,SlvAddr2,Ports_12_19, [Wrt_Data]
   I2COUT sda,SlvAddr2,Ports_29_31, [$01]  'bring OE & WE low (active)
   I2COUT sda,SlvAddr2,Ports_29_31, [$07]  'all control lines high (inactive)
   I2COUT sda,SlvAddr2,P_Cfg_12_15, [REP %10101010\2]  'make data lines inputs

Main2:        'read from RAM
   I2COUT sda,Slvaddr1,Ports_12_19, [RAM_addr0,RAM_Addr1,RAM_Addr2]
   I2COUT sda,SlvAddr2,Ports_29_31, [$4] 'bring OE & CE low (active)
   I2CIN  sda,SlvAddr2,Ports_12_19, [i2cdata]
   I2COUT sda,SlvAddr2,Ports_29_31, [$7]  'all control lines high
'   IF i2cdata = wrt_data THEN Main4
   DEBUG "data1 =",HEX2 i2cdata,TAB

Main4:
   RAM_Addr = RAM_Addr +1
   Wrt_Data = Wrt_Data +1
   GOTO main
 