Where is J5C?

Design Concepts
1

Well have nearly finished setting things up with the LPC board. Now I need 11 output lines, where is the best place to take them from? J10 is being used by the control surface so J5 seemed obvious but can only find J5A and B, no J5C like in the examples.

Anyone got any suggestions?

Thanks

S

2

You can use J28 instead, it has 4 IOs

{ 2, 13 }, // J28:SDA
{ 2, 11 }, // J28:SC
{ 2, 12 }, // J28:WS
{ 4, 29 }, // J28:MCLK
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The same functions as known for J5 are available.

From mios32_board.h:
[code]  
extern s32 MIOS32\_BOARD\_J28\_PinInit(u8 pin, mios32\_board\_pin\_mode\_t mode);  
extern s32 MIOS32\_BOARD\_J28\_Set(u16 value);  
extern s32 MIOS32\_BOARD\_J28\_PinSet(u8 pin, u8 value);  
extern s32 MIOS32\_BOARD\_J28\_Get(void);  
extern s32 MIOS32\_BOARD\_J28\_PinGet(u8 pin);

Best Regards, Thorsten.

3

Thats great, many thanks.

What I’m trying to do is to drive an 8 bit chip, so 8 data lines and 3 control lines. Looking at the board and schematic, might it be better to use a couple of 595’s into J19? Looks like a DIn could be connected there and the AOut commands used?

What is the maximum number 595’s that could be connected this way?

Thanks again.

4

What I’m trying to do is to drive an 8 bit chip, so 8 data lines and 3 control lines. Looking at the board and schematic, might it be better to use a couple of 595’s into J19?

If it’s working at 5V level, using a shift register is the best choice anyhow so that you will get level-shifting “for free”

Looks like a DIn could be connected there and the AOut commands used?

Yes!

What is the maximum number 595’s that could be connected this way?

It only depends on your timing requirements and buffers which are added between shift registers if the load gets too high.

I experienced that with up to 16 DIN/DOUT registers, no additional buffers are required (cables between shift registers should be short!)

The timing depends on the bitrate you are planning to use. Multiply it with the number of bits and you will get the delay which is caused by the transfers.

If you would explain more details about your project, I could give you more explicit hints…

Best Regards, Thorsten.