Hi Experts,
I have worked with modems in the past quite a lot, and have never had this issue before, so I am putting this question out in the hope that somebody else has!
I have a new brand of modem than I usually use as I am developing a project at home for personal use, so I am trying to keep the costs down, they are Dynamode 56k fax / data modems, they use the AGERE (Lucent) chipset, which I have the AT manual for, all seems normal, I configured as I should, did a modem to modem dial, all fine. I also have a PIC16F887 connected to a relay and plugged into the PC serial port all is well, pair them up and everything stops working!
The MAX232 is wired correctly, and the baud rate is all ok.
I have a couple of issues with the system so far,
1) The modem will not "transmit" any result codes if I do not "initialise" it by sending an AT command, it can be literally AT and it will work fine, so I send ATZ to activate the profile, all fine.
2) I have a MOXA DataScope utility which hooks onto the serial port and tells me what is being sent / recieved the sequence is as follows:
a) PIC Powers up
b) Sends ATZ <CR> to the modem
c) Modem sends OK <CR>
d) From the other modem I ATD XXXXXX (Number)
e) PIC Modem recieves 3 RING <CR>'s then answers
f) Both Modems handshake and CONNECT 9600 <CR> appears on the ports
-
Now, at this stage I would have hoped that a direct connection would be present, I can send data from the dialling modem and it will pick it up on the MOXA scope, and i can see it sending the data to the PIC, however, at this stage the PIC appears to have "locked up", when I re-apply power to the PIC I get:
ATZ <CR> sent from the PIC, and appears on the dialling modem (remember we are now in online mode, not command mode) and I can send and receive data happily.
However, when I try and send data, and the PIC hasn't finished transmitting it's feedback i.e. "Relay On" / "Relay Off", the PIC locks up again.
I am using HITECH C 9.65 Lite and the printf to send the data to the serial port, and the standard getch and putch routines from the compiler.
Does anybody know why my PIC is locking up?
I always thought any errors / overflows are cleared automatically, maybe I am wrong?
I dont know if it is "locking" up, but the UART certainly does, even echoing characters from the port stops working after the modem rings and connects.
Wilksey
I have worked with modems in the past quite a lot, and have never had this issue before, so I am putting this question out in the hope that somebody else has!
I have a new brand of modem than I usually use as I am developing a project at home for personal use, so I am trying to keep the costs down, they are Dynamode 56k fax / data modems, they use the AGERE (Lucent) chipset, which I have the AT manual for, all seems normal, I configured as I should, did a modem to modem dial, all fine. I also have a PIC16F887 connected to a relay and plugged into the PC serial port all is well, pair them up and everything stops working!
The MAX232 is wired correctly, and the baud rate is all ok.
I have a couple of issues with the system so far,
1) The modem will not "transmit" any result codes if I do not "initialise" it by sending an AT command, it can be literally AT and it will work fine, so I send ATZ to activate the profile, all fine.
2) I have a MOXA DataScope utility which hooks onto the serial port and tells me what is being sent / recieved the sequence is as follows:
a) PIC Powers up
b) Sends ATZ <CR> to the modem
c) Modem sends OK <CR>
d) From the other modem I ATD XXXXXX (Number)
e) PIC Modem recieves 3 RING <CR>'s then answers
f) Both Modems handshake and CONNECT 9600 <CR> appears on the ports
-
Now, at this stage I would have hoped that a direct connection would be present, I can send data from the dialling modem and it will pick it up on the MOXA scope, and i can see it sending the data to the PIC, however, at this stage the PIC appears to have "locked up", when I re-apply power to the PIC I get:
ATZ <CR> sent from the PIC, and appears on the dialling modem (remember we are now in online mode, not command mode) and I can send and receive data happily.
However, when I try and send data, and the PIC hasn't finished transmitting it's feedback i.e. "Relay On" / "Relay Off", the PIC locks up again.
I am using HITECH C 9.65 Lite and the printf to send the data to the serial port, and the standard getch and putch routines from the compiler.
Does anybody know why my PIC is locking up?
I always thought any errors / overflows are cleared automatically, maybe I am wrong?
I dont know if it is "locking" up, but the UART certainly does, even echoing characters from the port stops working after the modem rings and connects.
Wilksey
