Differences

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--- boards:sbc:sbc_v2:minimum-build [2018/07/08 10:28]
b1ackmai1er [Crystals and Oscillators.]
+++ boards:sbc:sbc_v2:minimum-build [2019/06/10 11:10] (current)
b1ackmai1er [Use flash memory instead of UV-erasable EPROM]
@@ Line 27: / Line 27: @@
 ===== Real Time Clock =====
-ECB SBC board features Dallas DS1302 Real Time Clock. It can be used for time keeping and also it has a few bytes non-volatile memory (NVRAM), that could be used for example, for storing system configuration. Currently (Jan 2012) BIOS doesn't support RTC functions, and RTC components could be omitted.
+ECB SBC board features Dallas DS1302 Real Time Clock. It can be used for time keeping and also it has a few bytes non-volatile memory (NVRAM), that could be used for example, for storing system configuration.
   * U18 (74LS174)
@@ Line 47: / Line 47: @@
   * U22 (Max232)
   * C24-C28 (1uF capacitors)
-  * Bridge pin's 7-10 and 8-9 in the Max232 component position.
+  * Bridge pins 7-10 and 8-9 in the Max232 component position.
+  * Bridge pins 14-11 and 13-12 in the Max232 component position if hardware flow control is required.
 Examples of minimum connections required:
@@ Line 57: / 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 65: / 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|
-\\
+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:
+Example starting with an AT27C080 EPROM and swapping to a AT49F040A FLASH chip.
-==== Use CMOS 74HCT or 74AHCT ICs instead of the TTL 74LS ====
+  - 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
-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.
+  - Change to secondary storage directory.
+  - Remove EPROM
-==== Use MAX232 alternative. ====
+  - 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.
-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).
+  - Run FLASH.COM i.e. FLASH /WRITE SBC.ROM
+  - Reboot
-==== 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.
-===== 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}}|
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@@ Line 110: / Line 100: @@
 ==== 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}}
 ===== Crystals and Oscillators. =====
@@ Line 122: / Line 115: @@
 |{{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 you should be able to run the CPU off the UARTY 1.8432 clock.
+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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