' ****************************************************************
' * File:  gmbsere.bas  -  Ver. 1.1                               *
' * Compiler:  PIC Basic PRO                                     *
' * IDE: MicroCode Studio Plus                                   *
' * Compiler Version: 2.45                                       *
' * Boards: GMM 4620 + GMB HR168                                 *
' *   GRIFO(R)   via Dell'Artigiano 8/6                          *
' *   40016 S. Giorgio di Piano (BO)                             *
' *   Tel. +39 051 892052                   Fax. +39 051 893661  *
' *   http://www.grifo.com                  http://www.grifo.it  *
' * by Graziano Gaiba                              08.02.05      *
' ****************************************************************
'
' This demo is a simple example of communication capableto work
' with all electric protocols available on CN2 (RS 232, RS 422,
' RS 485, current loop or TTL).
' In detail, through high level functions, it is possible to
' program baud rate from console, then each character received
' from serial port is sent to the port itself; reception of
' character 'r' decides how to manage the communication direction
' (signal DIR) for RS 422 and RS 485.
'
' Rel 1.1 - by Graziano Gaiba
' Demo program for low level EUSART usage with GMB HR168 driven
' by Mini Module GMM 4620
'
'
' ******************** Compiler definitions **********************
'
DEFINE OSC 10 ' Oscillator frequency 9,8304 MHz
'DEFINE HSER_RCSTA 90h  ' Enable EUSART serial receiver
'DEFINE HSER_TXSTA 20h  ' Enable EUSART serial transmitter
'DEFINE HSER_BAUD 19200 ' Baud Rate
'
' ******************* Constants declaration **********************
'
RTCSLA con $A0
I2C_BUFFER_SIZE con 10
'
' ******************** Variables declaration *********************
'
' Generic variables
i var byte
scelta var byte
di var byte
do var byte
'
' Used by I/O management procedures
port_val var byte  ' Value read or to be written to the I/O
'
' Used by low level EUSART management
char_to_tx var byte
char_rx var byte
kbhit var bit
'
'
'************************** Main Program *******************************
'
main:
    gosub Init_cpu
    ' Turn OFF relays
    port_val = 0
    gosub set_relays
    ' We need low level communication because DIR signal is not managed by
    ' PIC BASIC PRO high level instructions
    ' Disable auto baud-rate detection, 8 bit baud-rate generator
    baudctl = 0
    ' Value for baud rate 19200 and above settings
    '              Fosc
    ' SPBRG = --------------  -  1
    '          16 * BaudRate
    spbrg = 31
    ' High baud rate, Asynchronous mode, Enable transmitter, 8 bit transmission
    txsta = $24
    ' Enable receiver, 8 bit reception, Enable serial port
    rcsta = $90

    gosub clrscr
    hserout ["Low level EUSART demo Rel 1.1 for GMM 4620 rel 120304 and GMB HR168 rel 110104", 13, 10, 13, 10]
    hserout ["This demo shows how to configure the boards to use RS 232, TTL, RS 422, RS 485", 13, 10]
    hserout ["serial communication.", 13, 10]
    hserout ["Following the instructions allows to test RS 232 communication at low level,", 13, 10]
    hserout ["that means controlled by assembly instructions rather than BASIC commands.", 13, 10]
    hserout ["Next, RS 422 or RS 485 is configured and used. Also a direction signal", 13, 10]
    hserout ["is used in case of RS 485.", 13, 10]
    gosub wait_key
    hserout [13, 10, 13, 10]
    hserout ["In RS 232: on GMM 4620 set ON switches from 1 to 3, set OFF all others,", 13, 10]
    hserout ["EUSART management is made by PIC BASIC PRO, see documentation for more info.", 13, 10]
    hserout ["Set OFF switches 2 and 3, set ON switches 4 and 5, to have UART TTL signals", 13, 10]
    hserout ["directly to the socket pins.", 13, 10]
    hserout ["Connect J10 in 1-2.", 13, 10]
    gosub wait_key
    hserout [13, 10, 13, 10]
    hserout ["Test in RS232, then configure GMB for other protocol:", 13, 10]
    hserout ["turn off power supply, set DSW1:", 13, 10]
    hserout ["2=3=OFF,4=5=ON, then:", 13, 10]
    hserout [13, 10, 13, 10]
    hserout ["RS422:", 13, 10]
    hserout ["-install SN75176 or MAX483 on IC10 and IC11", 13, 10]
    hserout ["J5=2-3 J6,J7,J8=1-2 J10=1-2", 13, 10]
    hserout [13, 10, 13, 10]
    hserout ["RS485:", 13, 10]
    hserout ["-install SN75176 or MAX483 on IC10", 13, 10]
    hserout ["-J5=1-2 J6,J7,J8=1-2 J10=1-2", 13, 10]
    hserout [13, 10, 13, 10]
    hserout ["If at net termination->J3 and J4 connected", 13, 10]
    hserout ["R switches transmitter", 13, 10]
    ' DIR signal for RS 485 is PORTE.2
    trise.2 = 0
    porte.2 = 0
for_ever:
    gosub rx_status
    if kbhit = 1 then
        gosub rx_char
        if char_rx == "r" or char_rx == "R" then
            porte.2 = ! porte.2
        endif
        char_to_tx = char_rx
        gosub tx_char
    endif
    
    goto for_ever
end
'
' **************** Procedures definition ******************
'
'
' CPU and signals directions initialization
Init_cpu:
    ADCON1=$0f        ' Imposta come I/O digitale i pin AN0..12
    CMCON=$07         ' Imposta come I/O digitale RA0..4
    ' Optocoupled Inputs of CN1 are:
    ' IN1-1 <-> RA0
    ' IN2-1 <-> RA1
    ' IN3-1 <-> RB0
    ' IN4-1 <-> RB1
    ' IN5-1 <-> RA4
    ' IN6-1 <-> RC0
    ' IN7-1 <-> RC1
    ' IN8-1 <-> RC5
    trisa.0 = 1
    trisa.1 = 1
    trisa.4 = 1
    trisb.0 = 1
    trisb.1 = 1
    trisc.0 = 1
    trisc.1 = 1
    trisc.5 = 1
    ' Optocoupled Inputs of CN2 are:
    ' IN1-2 <-> RD0
    ' IN2-2 <-> RD1
    ' IN3-2 <-> RD2
    ' IN4-2 <-> RD3
    ' IN5-2 <-> RD4
    ' IN6-2 <-> RD5
    ' IN7-2 <-> RD6
    ' IN8-2 <-> RD7
    trisd = $ff
    ' Relay outputs of CN3 are:
    ' OUT A1 <-> RB4
    ' OUT A2 <-> RB5
    ' OUT B1 <-> RB6
    ' OUT B2 <-> RB7
    ' OUT C1 <-> RB3
    ' OUT C2 <-> RB2
    trisb = trisb & $03
    ' Relay outputs of CN4 are:
    ' OUT D1 <-> RA3
    ' OUT D2 <-> RC2 (J10 in position 3-4)
    trisa.3 = 0
    trisc.2 = 0
return
'
'
' Clear screen, sending 25 times CR + LF.
clrscr:
    for i= 0 to 24
      hserout [13, 10]
    next i
return
'
'
' Asks for a key press
wait_key:
    hserout ["Press a key..."]
wait_key_loop:
    hserin 1, wait_key_loop, [i]
return
'
'
' Procedure to set the status of the relays on connectors CN3 and CN4.
' According to the bits of port_val, each relay is turned ON
' (contact closed) or OFF (contact open).
' Bits of port_val have this meanging:
' -- CN3
' port_val.0 drives relay OUT A1
' port_val.1 drives relay OUT A2
' port_val.2 drives relay OUT B1
' port_val.3 drives relay OUT B2
' port_val.4 drives relay OUT C1
' port_val.5 drives relay OUT C2
' -- CN4
' port_val.6 drives relay OUT D1
' port_val.7 drives relay OUT D2
'
' Each bit has the following meaning:
'   bit              Meaning
'    0    Relay turned OFF (contact open)
'    1    Relay turned ON (contact closed)
set_relays:
    ' Relays are driven in complemented logic, so port_val must be
    ' complemented too
    port_val = port_val ^ $ff
    portb.4 = port_val.0
    portb.5 = port_val.1
    portb.6 = port_val.2
    portb.7 = port_val.3
    portb.3 = port_val.4
    portb.2 = port_val.5
    
    porta.3 = port_val.6
    
    portc.2 = port_val.7
return
'
'
' Transmission of a signle character using low level EUSART manipulation.
' Char to transmit must be in variable char_to_tx.
' It blocks until transmitters is free.
tx_char:
    ' Wait for transmitter available
    if txsta.1 = 0 then tx_char
    txreg = char_to_tx
return
'
'
' Check if a character has been received.
' If a character reception has been completed, variable kbhit is 1,
' otherwise it is 0.
rx_status:
    if pir1.5 = 1 then
        pir1.5 = 0
        kbhit = 1
    else
        kbhit = 0
    endif
return
'
'
' Reception of a signle character using low level EUSART manipulation.
' Character received is put in variable char_rx.
' Does NOT check if a character reception has been completed.
rx_char:
    char_rx = rcreg
return