Eshs
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=== PROM replacements === | === PROM replacements === | ||
- | H and V PROMs are MB7052. MB7052 may compatible with 82s129 proms | + | H and V PROMs are MB7052. MB7052 may compatible with 82s129 proms. The H PROM may overheat and require a heatsink. |
+ | |||
+ | For a possible replacement: http://callanbrown.com/index.php/flep-prom-replacement-adapters | ||
RGB PROM is MB7124. MB7124 are compatible with 82s147 proms. Haven't found any other replacement yet. | RGB PROM is MB7124. MB7124 are compatible with 82s147 proms. Haven't found any other replacement yet. |
Revision as of 23:03, 7 October 2020
Contents |
Esh's Aurunmilla
Memory Map
Address Range | Description |
0x0000-0x1FFF | ROM H8 |
0x2000-0x3FFF | ROM F8 |
0x4000-053FFF | ROM E8 |
0x6000-073FFF | ROM D8 |
0x8000-0x9FFF | ROM C8 |
0xA000-0xDFFF | Not connected |
0xE000-0xE7FF | CPU RAM (B8) |
0xF000-0xF7FF | Video RAM (F3) |
Z80 Port Map
Address Range | Direction | Description | ||||||||||||||
0xF0 | In | Control panel input. Only lower 6 data bits are used. Active low.
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0xF1 | In | Control panel input. Only lower 6 data bits are used. Active low.
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0xF2 | In | Control panel input. Only lower 6 data bits are used. | ||||||||||||||
0xF3 | In | Control panel input. Only lower 6 data bits are used. | ||||||||||||||
0xF4 | In/Out | LD-V1000 data. Writing queues a command to be sent on the next command strobe. Reading reads the most recent byte received during last the status strobe. | ||||||||||||||
0xF5 | Out | Misc value.
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0xF8 | Out | 0 disables start 1 button lamp. 1 enables. | ||||||||||||||
0xF9 | Out | Start 2 button lamp. 0 disables, 1 enables. | ||||||||||||||
0xFA | Out | 0 disables action button lamp. 1 enables. | ||||||||||||||
0xFB | Out | 0 disables joystick lamp. 1 enables. | ||||||||||||||
0xFC | Out | Not connected | ||||||||||||||
0xFD | Out | Not connected | ||||||||||||||
0xFE | Out | 0 holds IRQ' line high (disabled) by forcing a latch to be clear. 1 stops forcing latch to be clear, which allows IRQs to set the latch. | ||||||||||||||
0xFF | Out | 0 holds NMI' line high (disabled) by forcing a latch to be clear. 1 stops forcing latch to be clear, which allows NMIs to set the latch. |
Z80 Interrupts
NMI: Caused by LD-V1000 status strobe going low (becoming active)
IRQ: Caused by D2 output (pin 10) on vertical PROM (C6) transitioning from 0 to 1. This ends up being 60 Hz (vsync).
Video RAM Structure
Screen is divided into 32x32 tiles. The first tile is the top left.
0xF000-0xF3FF contain which tile to show.
0xF400-0xF7FF contain tile attributes. For example, 0xF400 would have attributes about the tile index at 0xF000.
Bit | Description |
0-3 | Which color palette to use for the tile. |
5-6 | Not used |
6-7 | Blink frequency. 0: no blinking, 1: blink at about 15 Hz, 2: blink at about 7.5 Hz, 3: blink at about 4.3 Hz ; The blink frequency is controlled by the Z80 program, and is not a hardware restriction. |
PROM replacements
H and V PROMs are MB7052. MB7052 may compatible with 82s129 proms. The H PROM may overheat and require a heatsink.
For a possible replacement: http://callanbrown.com/index.php/flep-prom-replacement-adapters
RGB PROM is MB7124. MB7124 are compatible with 82s147 proms. Haven't found any other replacement yet.
Newer EEPROMs may be fast enough. W27C512 may be a commonly available EEPROM.
Audio
Sampled from pin 1 of the audio connector on the Esh PCB (CN1).