Differences

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--- boards:sbc:sbc_v2:minimum-build [2018/07/08 10:51]
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 =====
@@ Line 64: / 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.
+  - 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
+  - Change to secondary storage directory.
+  - Remove EPROM
+  - 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.
+  - Run FLASH.COM i.e. FLASH /WRITE SBC.ROM
+  - Reboot
 \\
@@ Line 84: / 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}}
-==== Use CMOS 74HCT or 74AHCT ICs instead of the TTL 74LS ====
-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.
-==== Use MAX232 alternative. ====
-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).
-==== 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. =====