ZLF645 MAXIM [Maxim Integrated Products], ZLF645 Datasheet - Page 97

• Manufacturer Part Number: ZLF645
• Description: Flash MCUs with Learning Amplification
• Manufacturer: MAXIM [Maxim Integrated Products]

19-4572; Rev 0; 4/09
Caution:
Receiving Data Using the Polled Method
Receiving Data Using the Interrupt-Driven Method
9. Before disabling the transmitter, read the transmit completion status bit, UST[1]. If
Follow the steps below to configure the UART for polled data reception:
1. Write to the BCNST register to set the appropriate baud rate.
2. Write to the UART Control register (UCTL) to:
3. Check the receive status bit in the UART Status register, bit UST[7], to determine if
4. Read data from the UART Receive Data register.
5. Return to
The UART Receiver interrupt indicates the availability of new data (as well as error 
conditions).
Follow the steps below to configure the UART receiver for interrupt-driven operation:
1. Write to the UART BRG Constant registers to set the appropriate baud rate.
2. Execute DI instruction to disable interrupts.
3. Write to the Interrupt Control registers to enable the UART receiver interrupt and set
4. Clear the UART Receiver interrupt in the applicable Interrupt Request register.
5. Write to the UART Control register (UCTL) to:
6. Execute an EI instruction to enable interrupts.
Data written while the transmit enable bit is clear (UCTL[7]=0) will not be transmitted.
Data written while the transmit data status bit is clear (UST[2]=0) overwrites the pre-
vious value written, so the previous written value will not be transmitted. Disabling the
UART transmitter while the transmit completion status bit is clear (UST[1]=0) can
corrupt the byte being transmitted.
UST[1]=0, continue to monitor the bit until it changes to 1, which indicates that all
data in the Transmit Data and Internal Shift registers has been transmitted.
(a) Set the receive enable bit (UCTL[6]) to enable the UART for data reception
(b) Enable parity (if appropriate) and select either even- or odd-parity
the Receive Data register contains a valid data byte (indicated by a 1). If UST[7] is set
to 1 to indicate available data, continue to
(indicated by a 0), continue to monitor the UST[7] bit awaiting reception of the valid
data.
the appropriate priority.
(a) Set the receive enable bit (UCTL[6]) to enable the UART for data reception
(b) Enable parity, if appropriate, and select either even- or odd-parity
Step 3
to receive additional data.
Step
4. If the Receive Data register is empty
ZLF645 Series Flash MCUs
Product Specification
Operation

89