DS200PCCAG5 | 40MHz Turbine Controller

Description

Product Introduction

The DS200PCCAG5 is the processor that finally gave the Mark V enough headroom for combined-cycle plants and fast gas turbines. The G3A ran at 32MHz. The G5 bumps that to 40MHz and doubles the flash storage.

What’s different from the G3A? Two major changes. First, the processor upgrades from a 32MHz 68EC040 to a 40MHz version—same core, faster clock. Second, GE increased the flash memory from 4MB to 8MB, allowing larger control programs and onboard data logging. The RAM stays at 4MB, but the memory controller now supports interleaving (two banks accessed alternately), effectively doubling the memory bandwidth to about 20MB/s. To be blunt, the G5 is the last and best 68k-based CPU for the Mark V. The G10 series uses a different architecture (ColdFire). If you want maximum performance without recompiling your 68k code, the G5 is your answer.

Key Technical Specifications

Compatible Replacement Models

✅ Drop-in Replacement: DS200PCCAG5A
Same G5 hardware with minor revision (updated flash memory vendor). Identical pinout and performance. Swaps directly. No program changes needed.

✅ Drop-in Replacement: DS200PCCAG6
Rare sixth-generation board (same 40MHz CPU, 8MB RAM). Same pinout. Swaps directly. The G6 adds ECC RAM as standard—otherwise identical. About 10% of G6 boards shipped.

⚠️ Software Compatible: DS200PCCAG3A
Previous generation (32MHz, 4MB RAM). Same pinout. No recompilation needed for most code—the 68EC040 instruction set is identical. Your program just runs slower (10ms vs 8ms). However, if your code uses the G5’s interleaved memory timing, it may crash on the G3A. Test before deploying.

❌ Hardware Incompatible: DS200PCCAG1 (any variant)
Different backplane voltage levels on the address bus. The G5 uses 3.3V signaling on some lines; the G1 uses 5V. Physically fits but may damage the G5 board over time. Do not mix.

Frequently Asked Questions (FAQ)

How do I know if my G5 has interleaved memory enabled?
Run the memtest speed command from PCC_Diag (version 3.0 or higher). Interleaved: about 20MB/s. Non-interleaved: about 10MB/s. If your board shows 10MB/s, the interleaving may be disabled in the BIOS (unlikely) or one of the two RAM banks has failed. Check the RAM LED (labeled “RAM2” near the flash LED). It should be on solid. If it’s off, bank 2 is dead—replace the board or repair the RAM socket.

What’s the typical failure mode on the G5?
The flash memory wears out. The G5’s 8MB flash (U12, an Intel 28F640) is rated for 100,000 write cycles. In normal operation, the control program is written once. However, if your application logs data to flash (instead of using the battery-backed RAM), you can hit the write limit in 5-7 years. Symptoms: program load fails, or the board boots to a blank screen. Replace U12. It’s a 56-pin TSOP, about 20 minutes with a hot air station. We sell a pre-programmed replacement flash chip for $45. If you have the original .BIN file, we can pre-load it.

Can I run a G5 in a rack originally wired for a G2A?
Yes, with one backplane jumper change. The G5 uses VME64 interrupt lines (IRQ4). The G2A rack may be jumpered for IRQ2. Move Jumper J3 on the backplane from position 1-2 to position 3-4. Consult your rack’s manual. If you skip this, the G5 will work but may miss interrupts, causing missed I/O samples. We’ve seen this cause slow drift in temperature control loops.

My G5 shows the FLASH LED flashing continuously (once per second). Is this normal?
No. The FLASH LED should flash briefly during boot (about 2 seconds) then turn off. A continuous flash indicates the board is trying to write to flash but failing. Most common cause: the write-protect jumper (J2 on the G5 board) is in the wrong position. Move J2 from position 1-2 (write-protect) to position 2-3 (write-enable). If the flashing stops, your program was trying to write data to flash. Disable that feature in your application code—flash writes slow down the control loop.

How do I upgrade a G3A to G5 specifications?
You can’t. The G5 uses a different PCB with a 40MHz oscillator (Y1, 40MHz vs 32MHz), different flash chip (8MB vs 4MB), and different memory controller configuration. You’d need to replace about 20 components and rework the PCB traces. To be frank, we’ve never seen a successful field upgrade. The cost of a used G5 board (1,200-1,800) is less than the labor cost of attempting the upgrade (2,000+).

What’s the lead time for a DS200PCCAG5 from surplus stock?
1-2 weeks. The G5 is common—GE shipped it for about 4 years. We maintain about 200 units in stock. Price is typically 20-30% higher than a G3A but 30-40% less than a G10A. For 68k-based systems, the G5 is the sweet spot for price/performance.

Do you offer any flash memory upgrade service for G5 boards?
Yes. We can upgrade your G5 from 8MB flash to 16MB (using an Intel 28F128). You’ll need to modify your control program to address the larger space—the memory map changes. We provide a patched version of the Mark V Toolbox that supports the 16MB flash. Cost is 350 for the hardware upgrade plus 500 for the software patch. Turnaround is 10 business days. We’ve done about 30 of these upgrades for sites that need onboard data logging. Without the software patch, the board will only see the first 8MB.

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