| Attachment | Size |
|---|---|
 Disk containing RSCOPE8K.SYSTEM, EPROM images, and source code | 140 KB |
This thread is a combination of info-dump and file-share for troubleshooting a non-responsive Apple IIe Platinum on Facebook, here.
RSCOPE8K.SYSTEM is a work-in-progress prototype for a "ramless scope" program that aims to help study and troubleshoot Apple computers. It can be run under ProDOS like any standard .SYSTEM file, but it adopts a "ramless" architecture so that these bits can be programmed into an 8K EPROM (2764) that can be installed in the EF ROM or CF ROM socket on an Apple //e to cold-start into RSCOPE8K even without any RAM -- even without a functioning IOU. (A video card is required to generate video without RAM or without an IOU.)
RSCOPE8K.27128 is a variant of "ramless scope" for burning into a 27128 EPROM. The addresses and pinouts should make it compatible with the EF ROM or CF ROM socket of an Apple //e, or the firmware socket of an Apple //c.
RSCOPE8K.27256 is a variant of "ramless scope" for burning into a 27256 EPROM. The addresses and pinouts should make it compatible with the EF ROM or CF ROM socket of an Apple //e, or the firmware socket of an Apple //c.
Because RSCOPE is a work-in-progress its command set is incomplete, but the following commands are currently implemented in the attached version:
- (0) GRID - the zero key initializes a 40x24 text screen grid of colon characters, fills page 2 with numeral "2" characters, and places 8 flashing markers at the left and right margins to help confirm the text scanner is working. The two groups of eight flashing blocks should be distinguishible even if the character generator is faulty.
- (1) CHARSET - four rows of characters are stored into text memory, stored in four distinct ways in order to help distinguish faulty RAM decoding vs video scanner issues.
- (2) PAGECOUNT - counts valid pages of DRAM and displays the page count in hexadecimal and decimal memory size in KiB. Will not run unless it can establish 2 bytes of zero-page RAM and at least 1 functioning address bit.
- (3) VAPORGRAM - uses PAGE2 video memory to transmit 8 datagrams through the video scanner, testing all 8 data bits eight times apiece.
- (4) IOSEL ROMs - displays first 8 bytes of each card's boot ROM in each expansion slot -- the Apple //e's 80-column firmware appears separately, labeled "AUX3" if present. Pascal Protocol and DISKID bytes are highlighted if present. If all 256 bytes of IOSEL firmware are stable, a Fletcher-16 checksum is printed.
- (6) not implemented, reserved for ZP memory test
- (7) not implemented, reserved for motherboard memory test
- (8) MBIO - motherboard IO probe uses PAGE2 video memory to transmit phase-parity pattern in the same manner as ONE LINER: Vaporshow for sensing active vs inactive bits.