[FWD] About the modem

Excuse me... That is, sorry already, All...! === Cut === From: Maxim Timonin To: Wladimir V.Bulchukey Subject: Questions about the modem, etc.. Date: Wednesday, November 21, 2001 11:33 AM I have some questions here. device of the Kondratieff modem circuit from a software point of view or can I have friends who understand this. Why am I interested in this? What I mean is that I have a computer - ATM-turbo2, which has a normal console mode 9hardware) 80x25, and CP/M 2.2 to boot. I recently found out that there are good terminals on the network for CP/M, as well as the UUCP program, but they were written for other computers and about Kondraty, Naturally, we had not heard of it. I would like to remake them so that on BBS without breaking lines (in 80x25 mode) and color climbing. That's why I'm interested low level programming: 1) How and through what ports information for the modem is received/sent, 2) What are the readiness signals, etc. 3) What is the function of a non-maskable interrupt in this controller and how is it service programmatically (I mean that in the BASIC-48 ROM it is used standard procedure with a corrected byte, but in CP/M mode this is why address #66 contains RAM, and you will have to do the work with NMI yourself... 4) Well, there are other features that I don’t know about, or forgot to mention. - Maxim. max_timonin@mail.ruIf you have any information, thanks in advance for your help. Maxim. === Cut === With the best - Wlodek. * [] * mailto: wlblack(sign)chat.ru http://wlodek.newmail.ru * <[ZX]> * http://wlodeks.boom.ru [500:95/462@ZXNet] [2:5016 Forever] [Golyanovo] [Radio "Retro" 72.92 MHz]

Press RESET immediately, Wladimir! 21 Nov 01 23:39, Wladimir Bulchukey wrote to All: WB> device of the Kondratieff modem circuit from a software point of view or ^^^^^^^^^^^^^^^ In CP/M in its original form it cannot work with NMI. WB> 1) How and through what ports information is received/sent for WB> modem, The address is calculated like this: 0xF0EF + (0x0800 if NMI interrupts are disabled) + (register_address*0x100) The interrupt enable trigger from the modem switches only when output to the modem ports. WB> 2) What are the readiness signals, etc.. At the modem? RTFM dock on the serial port chip. WB> 3) What is the function of the non-maskable interrupt in this controller Generated as an interrupt from the modem. WB> and how to programmatically service it (I mean that in the BASIC-48 ROM WB> it uses the standard procedure with the corrected byte, and WB> in CP/M mode at this address #66 there is RAM, and work with NMI WB> you'll have to do it yourself... And nothing will work, there is one of the system FCBs in CP/M. Disconnect NMI and connect the interrupt to INT.INT on the computer ----RRRRR-+-- INT on the processor | to | |/-------+ IRQ on modem ---| b | uh | _|_ GND Transistor type KT315, ~500 ohm resistor. In software, such interrupts are processed simply: when an interrupt is received first, the modem handler is called if there is no request status in the register, then this is a timer interrupt. Of course, many timer interrupts are like this will be skipped, but in the case of NMI they would also be skipped... That is, for normal operation of communication programs more complex than a terminal emulator (yes, at least the same X,Y,Z-MODEM) you desperately need a hardware clock, otherwise there will be timeouts will be considered 'out of the blue'. WB> 4) Well, other features that are not mentioned WB> I know, or I forgot to mention. You don't know what you want.