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Both sides previous revision Previous revision Next revision | Previous revision | ||
gs1900-48 [2022/04/18 12:30] – Move firmware section up svanheule | gs1900-48 [2023/01/19 16:36] (current) – Serial header pin-out svanheule | ||
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2 Uplink ports are SFP cages which support 1000 Base-X tmini GBIC modules. | 2 Uplink ports are SFP cages which support 1000 Base-X tmini GBIC modules. | ||
- | Power is supplied via a 230 volt mains connector. The board has a hard reset switch SW1, which is is not reachable from the outside. J4 provides a 12V RS232 serial connector which is connected through U8 to the 3.3V UART of | + | Power is supplied via a 230 volt mains connector. The board has a hard reset switch SW1, which is is not reachable from the outside. J4 provides a 12V RS232 serial connector |
the RTL8393. Conversion is done by U8, a SIPEX 3232EC. To connect to the UART, wires can be soldered to R603 and R602. | the RTL8393. Conversion is done by U8, a SIPEX 3232EC. To connect to the UART, wires can be soldered to R603 and R602. | ||
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{{wiki: | {{wiki: | ||
- | === Hard reset circuit === | + | ==== JTAG ==== |
+ | The board has an unpopulated eJTAG header. The SMD resistor configuration is such that the interface is disabled by default. To be able to use the JTAG interface, the following changes need to be made: | ||
+ | * R171 permanently asserts nTRST. Move R171 (pull-down) to R525 (pull-up) to allow remote assertion of nTRST. | ||
+ | * R48 is unpopulated, | ||
+ | * Add 2×7 pin header, or at least add connections to TDI, TDO, TCK, TMS and (one) GND pins. | ||
+ | |||
+ | With these modifications, | ||
+ | |||
+ | < | ||
+ | Info : JTAG tap: auto0.tap tap/device found: 0x00001001 (mfg: 0x000 (< | ||
+ | Info : JTAG tap: auto1.tap tap/device found: 0x00000001 (mfg: 0x000 (< | ||
+ | </ | ||
+ | |||
+ | ==== Hard reset circuit | ||
{{wiki: | {{wiki: | ||
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* [[https:// | * [[https:// | ||
- | {{tag> | + | {{tag> |