• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 30 subscribers
  • Views 425 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

RM57L843: EMIF_nWAIT pin usage

SY Yoon
Genius 3381 points
Part Number: RM57L843
Other Parts Discussed in Thread: HALCOGEN

Hi,

I connected two devices to the EMIF_nWAIT pin of EMIF.

The EMIF_nWAIT pin is connected to the busy pins of DPRAM and ET1100. 

Can the EMIF_nWAIT be used as GPIO while ET1100 is enabled? (DPRAM is disabled)

If the pin is busy when executing the write command, I want to stop the write attempt.

I want to manually control the write attempt.

Is this possible?

  • 0
    TI__Guru**** 197126 points

    Hi,

    The EMIF_nWait can be used as GPIO. To use this pin as GIO, please set bit 24 and clear bit 26 of PINMMR10. The easier way is to use HALCoGen to configure the pinmux.

    The external wait cycles is determined by nWAIT input signal. If nWAIT is asserted, the EMIF begins inserting extra strobe cycle into the operation until the nWAIT pin is deactivated by the external device. But the nWAIT pin cannot be used to extend the strobe period indefinitely. The maximum number of EMIF Clock cycles (1~0xFF+1) is defined in AWCC register 

  • 0 in reply to QJ Wang
    Genius 3381 points

    Hi, 

    QJ Wang said:

    The EMIF_nWait can be used as GPIO. To use this pin as GIO, please set bit 24 and clear bit 26 of PINMMR10. The easier way is to use HALCoGen to configure the pinmux.

    I configured P3 pin as EMIF_nWait  and GIOB_7.

    The GIOB_7 is also mapped to the GPIO interrupt. 

    When the EMIF_nWait is asserted, GPIO interrupt is occurred. 

    My question is whether the EMIF_nWait pin can be used simultaneously with the GPIO function.

    In my test, it seemed possible. 

    QJ Wang said:

    The external wait cycles is determined by nWAIT input signal. If nWAIT is asserted, the EMIF begins inserting extra strobe cycle into the operation until the nWAIT pin is deactivated by the external device. But the nWAIT pin cannot be used to extend the strobe period indefinitely. The maximum number of EMIF Clock cycles (1~0xFF+1) is defined in AWCC register 

    If it exceeds the maximum clock defined in AWCC, what is the next action?

    Does it keep trying to write? or does it stop trying to write?

    I want the write attempt to stop when counter is expired.

  • 0 in reply to SY Yoon
    TI__Guru**** 197126 points

    Hi SY,

    P3 in can be used as either nWAIT or GIOB[7]. It cannot be used for both at a time.

    There are two terminals for GIOB[7] input: F1 and P3. T1 is selected by default. If you change it to P3, PINMMR87[17:16] needs to be programmed (10b or 0x2).

    If the EMIF_nWAIT pin is not deactivated within the time specified in AWCC, the EMIF resumes the access cycle, registering whatever data is on the bus and proceeding to the hold period of the access cycle. This situation is referred to as an Asynchronous Timeout which will generate an Asynchronous Timeout interrupt if the interrupt is enabled (INTMSKSET).