Data sheet for standard Motorla SPI component seems to be worded incorrectly

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
JoWi_3984961
Level 4
Level 4
First like received First like given

Jan. 22, 2019

The SPI data sheet states on page 103 of 216: (Document Number: 002-20171 Rev. *B)

"

RX FIFO

The interrupt or DMA trigger output signal remains active until the number of data elements in the RX FIFO is greater than the value of RX FIFO level.

For example, the RX FIFO has 8 data elements and the RX FIFO level is 0. The DMA trigger signal remains active until DMA does not read all data from the RX FIFO.

"

I would think it should be:

RX FIFO

The interrupt or DMA trigger output signal remains active until the number of data elements in the RX FIFO is less than (or equal to ?) the value of RX FIFO level.

For example, the RX FIFO has 8 data elements and the RX FIFO level is 0. The DMA trigger signal remains active until DMA does read all data from the RX FIFO.

Does anyone agree? And now I must question also, what happens when the number of data elements in the RX FIFO is equal to the value of the RX FIFO level?

0 Likes
1 Solution
Ekta
Moderator
Moderator
Moderator
750 replies posted First like given 250 solutions authored

Hi john

We have verified that:

RX FIFO

The interrupt or DMA trigger output signal remains active until the number of data elements in the RX FIFO is greater than the value of RX FIFO level.

For example, the RX FIFO has 8 data elements and the RX FIFO level is 0. The DMA trigger signal remains active until DMA does not read all data from the RX FIFO

Also when the number of data elements in the RX FIFO is equal to the value of the RX FIFO level no interrupt or DMA trigger output is generated.

Thanks

Ekta

View solution in original post

0 Likes
3 Replies
himam_31
Employee
Employee
50 likes received 25 likes received 10 likes received

Hello John,

I just want to check if you are facing the behavior as mentioned in the above interaction. If yes can you please share your test example with us. We would like to review this.

Thanks,

Hima

0 Likes

I no longer need this peripheral. I was just concerned that the document cited was difficult to read and/or incorrect.

0 Likes
Ekta
Moderator
Moderator
Moderator
750 replies posted First like given 250 solutions authored

Hi john

We have verified that:

RX FIFO

The interrupt or DMA trigger output signal remains active until the number of data elements in the RX FIFO is greater than the value of RX FIFO level.

For example, the RX FIFO has 8 data elements and the RX FIFO level is 0. The DMA trigger signal remains active until DMA does not read all data from the RX FIFO

Also when the number of data elements in the RX FIFO is equal to the value of the RX FIFO level no interrupt or DMA trigger output is generated.

Thanks

Ekta

0 Likes