NFCのトピックRe: PN5180 register read error by default

PN5180 register read error by default

liumanjinkobe — Wed, 20 Mar 2019 07:12:47 GMT

Hello,

Now i cann't get the right value from any register use command 0x04.

I think the busy line is right.

I describe my trouble in attachment in detail.

Thanks for your help.

Liu

Re: PN5180 register read error by default

jimmychan — Thu, 21 Mar 2019 04:22:23 GMT

The content of the register is returned in the 4 byte response.

Re: PN5180 register read error by default

liumanjinkobe — Thu, 21 Mar 2019 05:44:00 GMT

Hello,

Yes, but i cann't get the right response.

Re: PN5180 register read error by default

jimmychan — Thu, 21 Mar 2019 06:06:24 GMT

I saw you only receive one byte.

According to the datasheet, this is the recommendation for the BUSY line handling by the host:
1. Assert NSS to Low
2. Perform Data Exchange
3. Wait until BUSY is high
4. Deassert NSS
5. Wait until BUSY is low

Have you try to read/write the other register? e.g. system_config

Re: PN5180 register read error by default

liumanjinkobe — Thu, 21 Mar 2019 06:47:47 GMT

Yes,other registers are 0xffffffff also.

Now i want to send 0x04 command to get the 32bit of 0x00 register.

After send 0x04, i can find busy line has become high,Now i want to know if i should Deassert
NSS to let busy line recover low.And then i can send 0x00 to get the response.

For i know if busy line is high,PN5180 cann't get 0x00 data.

Thanks.

Re: PN5180 register read error by default

liumanjinkobe — Thu, 21 Mar 2019 06:58:00 GMT

The BUSY line is used to indicate that the system is BUSY and cannot receive any data
from a host. Recommendation for the BUSY line handling by the host:
1. Assert NSS to Low
2. Perform Data Exchange
3. Wait until BUSY is high
4. Deassert NSS
5. Wait until BUSY is low

i want to know Perform Data Exchange is send 0x04+0x00+32bit response or only send 0x04.

Because after i send 0x04,the busy has become high.

Re: PN5180 register read error by default

jimmychan — Wed, 27 Mar 2019 08:02:56 GMT

Yes, when BUSY is high, need to deassert the NSS.