Can LPC546xx EMC stall access to external device

[isaotakashima]

We would like to use the DPRAM (Dual Port RAM) in our product using LPC54605.

https://ja.idt.com/document/dst/713040-datasheet 

The DPRAM will assert BUSY signal to indicate that write access on other port side.

If assert BUSY signal, LPC54605 should insert wait state automatically until negate BUSY signal.

However I cannot find pin to connect BUSY signal of DPRAM.

Which pin can connect BUSY signal to insert wait state?

Please reply as soon as possible.

Best regards,

Takashima

[xiangjun_rong]

Hi, Takashima,

As you know that the EMC of LPC546xx does not support Transfer Acknowledge signal, so you can not extend memory access timing by the signal. I think the BUSY signal from Dual PORT RAM(DPRAM) is an open-drain output signal, you can connect the signal to GPIO pin(for example PORT0 or1), and you can configure the pin as interrupt source. When the busy signal interrupt happens, you know that conflict(writing the same address from dual port)  occurs, in the pin interrupt ISR, you can rewrite again or do whatever you like.

Hope it can help you

BR

XiangJun rong