Panasonic MN101C00 user manual Synchronous Serial Interface, Overview

Chapter 5 Serial Functions

5-2 Synchronous Serial Interface

5-2-1 Overview

A serial interface begins operation when data is written to the shift buffer. A bit counter is incremented at each 1-bit transfer. The transfer is complete when the counter overflows.

Bit transfers of an arbitrary 1 to 8 bits can be performed. The transfer bit count must be set before performing the transfer.

[☞ Section 5-2-3, "Serial

Interface Transfer Timing"]

5-2-2 Setup and Operation

■Transmission

(1)Select the synchronous serial interface by setting the SC0CMD flag of the serial interface 0 control register (SC0CTR) to "0."

(2)Select the transfer bit count with the SC0LNG2 to 0 flags of the serial interface 0 mode register 0 (SC0MD0). The transfer bit count can be set as 1 to 8 bits.

(3)Specify whether the start condition is enabled or disabled with the SC0STE flag of the SC0MD0 register.

(4)Specify the first bit to be transferred (MSB first or LSB first) with the SC0DIR flag of the SC0MD0 register.

(5)Select the valid edge of the clock signal with the SC0CE1 to 0 flags of the SC0MD0 register.

(6)When the clock source is an internal clock:

•Select the clock source with the SC0CK1 to 0 flags of serial interface 0 mode register 1 (SC0MD1).

•Set the SC0CKM flag of the SC0MD1 register specify whether or not the clock source frequency will be divided by 8.

•Select serial clock operation by setting the SC0SBTS flag of the serial interface 0 mode register 3 (SC0MD3) to "1."

•Set the SC0SBTM flag of the SC0MD3 register.

•Set bit 0 of the port 0 direction control register (P0DIR) to the output mode.

•Set bit 0 of the port 0 pull-up resistor control register (P0PLU).

94 Synchronous Serial Interface