Differences

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--- boards:sbc:sbc_v2:minimum-build [2019/01/15 03:56]
b1ackmai1er [Use flash memory instead of UV-erasable EPROM]
+++ boards:sbc:sbc_v2:minimum-build [2019/06/10 11:10] (current)
b1ackmai1er [Use flash memory instead of UV-erasable EPROM]
@@ Line 33: / Line 33: @@
   * X1 (32768 Hz crystal)
   * C9 (bypass capacitor)
 ===== NVRAM Controller =====
@@ Line 59: / Line 58: @@
 {{https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/boards/sbc/sbc_v2/sbcv2-ttlserial.png?nolink&160x110}}
-===== Component Substitution =====
 ===== Component Substitution =====
@@ Line 67: / Line 63: @@
 ==== Use flash memory instead of UV-erasable EPROM ====
-Flash memory is generally cheaper, easier to obtain, and easier to work with. It could be instantly erased, without UV eraser lamp, it doesn't need special voltages for programming (and theoretically can be reprogrammed in system). The only drawback of the flash memory, is lower storage capacity - 512 KiB vs. 1024 KiB for 27C080 EPROM (this limitation is due to number of pins in 32 pin package). Recommended flash parts are SST 39SF040 (Mouser), and AMD 29F040 (Jameco). Possibly other flash ICs, with lower capacity (such as 29F020, which is frequently found on older motherboards) can be used instead.
+Flash memory is generally cheaper, easier to obtain, and easier to work with. It can be instantly erased, without UV eraser lamp, it doesn't need special voltages for programming and can be reprogrammed in system. The only drawback of the flash memory, is lower storage capacity - 512 KiB vs. 1024 KiB for 27C080 EPROM (this limitation is due to number of pins in 32 pin package). Recommended flash parts are SST 39SF040, and AMD 29F040 (Jameco). Possibly other flash ICs, with lower capacity (such as 29F020, which is frequently found on older motherboards) can be used instead.
 ^Device - Jumper^Size^K1^K6^K8|
 ^AT29C020^256Kb|1-2|2-3|None|
+^AM29F040B^512Kb|1-2|2-3|2-3|
 ^AT49F040A^512Kb|1-2|2-3|2-3|
+^SST39SF040^512Kb|1-2|2-3|2-3|
+^M27C4001^512Kb|1-2|1-2|None|
 ^AT27C080^1Mb|1-2|1-2|1-2|
 ^M27C801^1Mb|1-2|1-2|1-2|
-==== Use CMOS 74HCT or 74AHCT ICs instead of the TTL 74LS ====
+In the situation that you do not have an EPROM programmer it is best to obtain a copy of the ROMWBW in a FLASH format so it can be reprogrammed in-system using the FLASH utility. A HOTFLASH technique can be used if you want to swap from an EPROM to a FLASH chip without an EPROM programmer:
-CMOS 74HCT and 74AHCT logic ICs are usually cheaper than corresponding TTL ICs. They are also consume significantly less electricity. Note that some people reported problems with using these parts for ECB buffers / transmitters and also in SBC-188 (particularly using 74HCT373/74AHCT373 instead of 74LS373). But otherwise they should work just fine.
+Example starting with an AT27C080 EPROM and swapping to a AT49F040A FLASH chip.
-==== Use MAX232 alternative. ====
+  - Transfer new ROM image from PC to SBC-V2 secondary storage i.e. SDCard
+  - Copy FLASH.COM from B: to secondary storage i.e SDCard
-The original MAX232 or MAX232A parts can be expensive. Other vendors make compatible parts, that are significantly cheaper. For example Texas Instruments TRS202, or Intersil HIN232. These parts can also work with 0.1 uF capacitors (smaller, cheaper, you'll be buying them for bypass capacitors anyway).
+  - Change to secondary storage directory.
+  - Remove EPROM
-==== Disk storage without ECB backplane and Disk I/O board. ====
+  - Change jumpers to suit FLASH chip i.e. K1 unchanged, K6 from 1-2 to 2-3, K8 from 1-2 to 2-3.
+  - Insert FLASH chip. Insert pin 1 side first to ensure GND had contact first.
-You can install the 8255 PPI chip, and use the [[https://retrobrewcomputers.org/n8vem-pbwiki-archive/0/35845334/35845372/35846055/index.htm|PPIDE]] mini board to connect an IDE drive or a compact flash card.
+  - Run FLASH.COM i.e. FLASH /WRITE SBC.ROM
+  - Reboot
-===== Crystals and Oscillators. =====
-The ECB SBC V2 has been been overclocked successfully, with speeds as high as 16Mhz reported by replacing the 4Mhz crystal.
-An elegant solution for replacing the TTL oscillator with standard crystals was identified and described by trick-1, with the benefit of variable clock rate flexibility for overclocking.
-Based on the circuit described here [[https://www.eleccircuit.com/crystal-oscillator-using-ttl/|https://www.eleccircuit.com/crystal-oscillator-using-ttl/ ]]<font inherit/inherit;;inherit;;rgba(255,255,255,0)>a 4/8/10/12/16/20 MHz</font> switchable clock circuit was implemented which demonstrated the maximum clock speed in his board was 10Mhz.
-|{{https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/boards/sbc/sbc_v2/photos/protoboard-trick-1.jpg?nolink&306x200|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_boards_sbc_sbc_v2_photos_protoboard-trick-1.jpg}}|{{https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/boards/sbc/sbc_v2/photos/overclock-trick-1.jpg?nolink&306x200|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_boards_sbc_sbc_v2_photos_overclock-trick-1.jpg}}|
-Untested but theoretically possible, you should be able to run the CPU off the 1.8432 UART clock by connecting pin 5 of P5 (CLK_UART) to P4 pin 5 (CLK_CPU).
-{{https://www.retrobrewcomputers.org//lib/plugins/ckgedit/fckeditor/userfiles/image/boards/sbc/sbc_v2/sbc-v2-clock.png?nolink&320}}
 \\
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 ==== Disk storage without ECB backplane and Disk I/O board. ====
-You can install the 8255 PPI chip, and use the [[https://retrobrewcomputers.org/n8vem-pbwiki-archive/0/35845334/35845372/35846055/index.htm|PPIDE]] mini board to connect an IDE drive or a compact flash card.
+You can install the 8255 PPI chip, and use the [[:boards:other:ppide|PPIDE]] mini board to connect an IDE drive or a compact flash card.
+{{https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/boards/other/ppide/on_sbcv2_2_.jpg?nolink&400x236|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_boards_other_ppide_on_sbcv2_2_.jpg}}