Wondered about the following: would it be possible to use the magnetic tape drive features of the Lynx for some purpose?
Some facts I gathered today:
- Pin 28 (TAPE1) and Pin 29 (TAPE0) of the Mikey chip are present (although they are connected to ground)
- The timers 1, 3, 5 and 7 refer to Mag0a, Mag0b, Mag1a and Mag1b respectively
- Addresses FD84 (MAGRDY0) and FD85 (MAGRDY1) appear to offer a 7th bit to signal "Mag tape ready" for the channels 0 and 1. The bit is reset on read.
- The addresses of the
- FD04 = TIM1BKUP MAGA
- FD0C = TIM3BKUP MAGB
- FD14 = TIM5BKUP MAGC
- FD1C = TIM7BKUP MAGD
- The addresses for timer static controls (TIMXCTLA, where X is 1, 3, 5 or 7) refer to magmode with bit $20.
"Unused in timers 0,2,4,6 / Magmode in timers 1,3,5,7 $20 ..1....."
- The documentation says: "The circuit for reading magnetic tape is in Mikey. However the Mikey ROM does not currently activate the tape mode. When the decision is made, the ROM may have to be changed. The alternative would be to use an external ROM that would activate the tape circuits."
- "The other 5 timers are for general software use. POOF. See the mag tape description."
- Pin 9 is MOTORON and is referred to from FD87 (SYSCTL1)
"FD87 = SYSCTL1.Control Bits.(W)
B1=power (1 = on)
B0= Cart Address Strobe (also counter reset) (was MotorOn)"
- Older chipsets might be needed. From the Epyx Development Kit source files, it mentions in harddefs.i in version 1.2 and 1.3 of the kit that magnetic tape related definitions have been removed.
Version 1.1 (in text file Release_1.1)"The following files have been removed, and should no longer be
referenced by your code:6502:include/aio2defs.i
"6502:include/harddefs.i - Removed MAGRDYx definitions
(MAGTAPE features are removed from new chips)
Added new stereo hardware definitions"
"6502:include/harddefs.i - removed the MAGxx names for timers
added READ_ENABLE bit definition for IODAT"
harddefs.i change log:
"* 7-Mar-90 SHL Removed MAGRDYx definitions"
"* 27-Jun-90 SHL Removed MAGxx alternate names for timers"
- Epyx Development Kit refers to:
* 2 Jan 89 -RJ Added TAPE_RECORDING definition and examples
* of calling tape-recording macros
Since most magnetic tape references have been removed around early 1990 (release 1.1 on 27-2-1990, release 1.2a in 29-3-1990, Release 1.3.3 in 28-6-1990), and the Lynx was released on September 1st, 1989 it might be that the hardware was changed after release of the first Lynx 1 devices.
Anyway, any ideas and opinions are welcome.
- Epyx Development Kit source code files