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slavefifo 16bit data width | Cypress Semiconductor

slavefifo 16bit data width

Summary: 2 Replies, Latest post by jaehojo on 08 Oct 2015 03:07 AM PDT
Verified Answers: 0
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jaehojo's picture
2 posts

To interfacing with external device, I'm trying to test using CYUSB3014.

I configured GPIF to slavefifo, and I checked operation correctly in case of 8 bit data width mode.

I tried to slavefifo 16 bit mode for increasing throughput.

But it is not working correctly.

Output data is Ok only DQ[7:0]. DQ[15:8] is always zero.

I guess, it is not losing even byte data.

Only 8 bit data is output.

For example, If I sent 0x12345678 data, then the following data is output each clock.

0x0078 0x0056 0x0034 0x0012.

The changes to the 16 bit mode are as follows :


     * BUS_WIDTH : 0 --> 1

     * ADR_CTRL : 0 --> 5

This was a reference to GPIF II designer example. (sync_slave_fifo_2bit.cydsn)

mady's picture
Cypress Employee
963 posts


We stronly recommend you to not edit the State Machine header file directly y writin to the registers, Please use the GPIF Ii SDesigner tool to generate the Header file for 16 Bit configuration.

Open the 8 Bit configuration in GPIF II designer tool, change the Bus width from 8 Bit to 16 Bit in the tool and then build it to get the header file.

FYI, the PIN_COUNT filed will also change when changing from 8 Bit to 16 Bit.


- Madhu Sudhan

jaehojo's picture
2 posts

I already generated 8 bit and 16 bit configuration using GPIF II designder tool.

And I did directly writin to the GPIF_BUS_CONFIG  register because there is no difference between 8bit and 16bit configuration except that register.

thank you.

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