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recipes/trs80: add instructions to save recv program to floppy

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This commit is contained in:
Virgil Dupras 2020-02-10 11:25:05 -05:00
parent 9d8aa3a0d0
commit bab18216aa
3 changed files with 36 additions and 9 deletions
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11
doc/trs80-4p.md
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@ -62,7 +62,7 @@
84-87-Wr Page Fix upr Memory Memory Invert 80/64 Select Select
mem bit 1 bit 0 video Bit 1 Bit 0
## Memory map
## System memory map
### Memory map 1 - model III mode
@ -95,6 +95,15 @@
0000-7fff RAM (32K) bank 1
8000-ffff RAM (32K) bank 2
## TRSDOS memory map
0000-25ff Reserved for TRSDOS operations
2600-2fff Overlay area
3000-HIGH Free to use
HIGH-ffff Drivers, filters, etc
Use `MEMORY` command to know value of `HIGH`
## Supervisor calls
SVC are made by loading the correct SVC number in A, other params in other regs,

32
recipes/trs80/README.md
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@ -56,7 +56,7 @@ The first step here is ensuring that you have bi-directional serial
communication. To do this, first prepare your TRS-80:
set *cl to com
setcomm (word=8, parity=no)
setcomm (word=8,parity=no)
The first line loads the communication driver from the `COM/DRV` file on the
TRSDOS disk and binds it to `*cl`, the name generally used for serial
@ -84,15 +84,18 @@ As stated in the overview, we need a program on the TRS-80 that:
That program has already been written, it's in `recv.asm` in this folder. You
can get the binary with `zasm < recv.asm | xxd`.
It's designed to run from offset `0x4000` and write received data in `0x3000`
and onwards.
How will you punch that in? The `debug` program! This very useful piece of
software is supplied in TRSDOS. To invoke it, first run `debug (on)` and then
press the `BREAK` key. You'll get the debug interface which allows you to punch
in any data in any memory address. Let's use `0x3000` which is the offset for
user apps.
in any data in any memory address. Let's use `0x4000` which is the offset it's
designed for.
First, display the `0x3000-0x303f` range with the `d3000<space>` command (I
First, display the `0x4000-0x403f` range with the `d4000<space>` command (I
always press Enter by mistake, but it's space you need to press). Then, you can
begin punching in with `h3000<space>`. This will bring up a visual indicator of
begin punching in with `h4000<space>`. This will bring up a visual indicator of
the address being edited. Punch in the stuff with a space in between each byte
and end the edit session with `x`.
@ -111,12 +114,13 @@ to `*cl`? that's it. But that's not our DCB.
To get your DBC, go explore that memory area. Right after the part where there's
the `*cl` string, there's the DCB address (little endian). On my setup, the
driver was loaded in `0x0ff4` and the DCB address was 8 bytes after that, with
a value of `0x0238`.
a value of `0x0238`. Don't forget that z80 is little endian. `38` will come
before `02`.
## Sending data through the RS-232 port
Once you're finished punching your program in memory, you can run it with
`g3000<enter>` (not space). Because it's an infinite loop, your screen will
`g4000<enter>` (not space). Because it's an infinite loop, your screen will
freeze. You can start sending your data.
To that end, there's the `tools/pingpong` program. It takes a device and a
@ -141,4 +145,18 @@ and return. That should bring you back to a refreshed debug display and you
should see your sent content in memory, at the specified address (`0x3040` if
you didn't change it).
## Saving that program for later
If you want to save yourself typing for later sessions, why not save the
program you've painfully typed to disk? TRSDOS enables that easily. Let's say
that you typed your program at `0x4000` and that you want to save it to
`RECV/CMD` on your second floppy drive, you'd do:
dump recv/cmd:1 (start=x'4000',end=x'4030',tra='4000')
A memory range dumped this way will be re-loaded at the same offset through
`load recv/cmd:1`. Even better, `TRA` indicates when to jump after load when
using the `RUN` command. Therefore, you can avoid all this work above in later
sessions by simply typing `recv` in the DOS prompt.
**WIP: that's where we are for now...**

2
recipes/trs80/recv.asm
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@ -1,4 +1,4 @@
ld hl, 0x3040 ; memory address where to put contents.
ld hl, 0x3000 ; memory address where to put contents.
loop:
ld a, 0x03 ; @GET
ld de, 0xffff ; replace with *CL's DCB addr