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blog:transputer_tmb08_repair [2020/11/24 12:42] – [Completed Modifications] john | blog:transputer_tmb08_repair [2020/12/09 08:29] (current) – [IO Speed Tuning] john | ||
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==== Restoring Original Specifications ==== | ==== Restoring Original Specifications ==== | ||
+ | |||
+ | **[Update - November 2020]** | ||
It's clear that towards the end of the life of the Transputer, some of the excess stock of these cards was repurposed to be used as dedicated RS422 interface controllers - they saved money by not including the programmable link switch (not needed if you don't have any Transputer processors), | It's clear that towards the end of the life of the Transputer, some of the excess stock of these cards was repurposed to be used as dedicated RS422 interface controllers - they saved money by not including the programmable link switch (not needed if you don't have any Transputer processors), | ||
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I've also now desoldered the two bridge wires from the rear of the card. In theory, this should now be a perfectly working TMB08. I just need to test it in a working DOS PC.... | I've also now desoldered the two bridge wires from the rear of the card. In theory, this should now be a perfectly working TMB08. I just need to test it in a working DOS PC.... | ||
+ | |||
+ | ===== Testing ===== | ||
+ | |||
+ | The board has a number of dip switches and jumpers to set, the main ones being a 6 way dip-switch (S1-S6) | ||
+ | |||
+ | * S1 + S2: On (port address 0x150) | ||
+ | * S3: On (20Mbit link speed) | ||
+ | * S4: Off (slot 1-9 controlled by slot 0) | ||
+ | * S5: On (slot 0 controlled by PC interface, not edge connector) | ||
+ | * S6: Not supported | ||
+ | |||
+ | The second configuration being a 12 pin jumper block just below the dip switch. For a single (or master) TMB08, it must be configured as below: | ||
+ | |||
+ | {{: | ||
+ | |||
+ | Initially I couldn' | ||
+ | |||
+ | {{: | ||
+ | |||
+ | Ultimately I reinserted the card several times, test again, left it a couple of days, reinserted it and tried again - this time it worked; although I completely filled all the TRAM slots, so perhaps that was an issue? | ||
+ | |||
+ | {{: | ||
+ | |||
+ | //In hindsight, later versions of the ispy tool (anything above v233.1) appear to vomit, repeatedly, when scanning my TMB08. If I stick to ispy v233, then everything is detected normally.// | ||
+ | |||
+ | ===== IO Speed Tuning ===== | ||
+ | |||
+ | The default link speed from the root transputer to the PC host is moderately low; in the order of **270-280KBytes/ | ||
+ | |||
+ | * Standard BIOS settings are: | ||
+ | * **1/4** Bus clock as ISA speed (33MHz/4 = 8.// | ||
+ | * **8** clock cycles as 8bit ISA IO recovery time | ||
+ | |||
+ | I tried a sequence of changing ISA clock and then 8bit IO recovery time, testing in between each change via //ispy// to verify host IO link speed. These are the results: | ||
+ | |||
+ | {{: | ||
+ | |||
+ | The first increase in IO speed comes from both increasing the ISA clock from the standard 8MHz (bus / 4) to 11MHz (bus / 3), which gains an additional **22-24KBytes/ | ||
+ | |||
+ | CPU level 1 and motherboard level 2 caches are already optimal (write-back supported on both) and memory timings are already set correctly for the type and speed of the modules installed, so there are no further gains to be made there. | ||
+ | |||
+ | Still, the overall improvement from the base setting is approximately **55-56KBytes/ | ||
+ | ===== Transputer Network Configuration ===== | ||
+ | |||
+ | Now that the TMB08 is up and running, I need a way to network both this and my older, working Transtech TMB04 together. | ||
+ | |||
+ | Fortunately the TMB08 brings out a load of Transputer 20Mbit connections to the 37-way D-connector on the card. This allows you to physically connect multiple cards and multiple transputer networks together. | ||
+ | |||
+ | The TMB08 has 10 slots on the cards, with each slot being able to be software configured to other slots by the onboard C004 programmable switch. The switch also has enough free ' | ||
+ | |||
+ | Here's the physical connections that I //think// are needed from a single TMB08 working as master, with a TMB04 as a slave with all 5 transputers on the TMB04 connected independently: | ||
+ | |||
+ | {{: | ||
+ | |||
+ | This still leaves 3 pairs of Transputer links available in case I add several more cards. | ||
+ | |||
+ | If connecting to another C004 managed card (like a real Inmos B008, or another TMB08), then you also need to connect // |