User Manual

Table Of Contents
Jennic
© Jennic 2009 JN-DS-JN5148-001 1v2 55
Preliminary
all the data specified in the length field to the JN5148. The master must then deassert IP_SEL to show the transfer
is complete.
The master may initiate a transfer to read data from the JN5148 by asserting the slave select pin, IP_SEL, and
generating its status byte on IP_DI with RXRDY set. After receiving the status byte from the JN5148, it should check
that the JN5148 has a buffer ready by reading the TXRDY bit of the received status byte. If the TXRDY bit is 0,
indicating that the JN5148 does not have data to send, it must terminate the transfer by deasserting IP_SEL unless it
is transmitting data to the JN5148. If the TXRDY bit is 1, indicating that the JN5148 can send data, then the master
must generate a further 8 clocks on IP_CLK in order to receive the message length on IP_DO. The master must
continue clocking the interface until sufficient clocks have been generated to receive all the data specified in the
length field from the JN5148. The master should then deassert IP_SEL to show the transfer is complete.
Data can be sent in both directions at once and the master must ensure both transfers have completed before
deasserting IP_SEL.