sak-c868p-1rr Infineon Technologies Corporation, sak-c868p-1rr Datasheet - Page 236

• Manufacturer Part Number: sak-c868p-1rr
• Description: 8 - Bit Cmos Microcontroller
• Manufacturer: Infineon Technologies Corporation

Figure 9-4
9.2.1
The first action of the bootstrap loader is to synchronize the baud rate between the MCU
and host. It is performed in the following steps.
STEP 1: Initialize serial interface for reception and Timer 2 for baud rate measurement.
STEP 2: Wait for test byte (80
STEP 3: Synchronize the baud rate to the host
STEP 4: Send Acknowledge byte (55
STEP 5: Enter Phase II.
The serial port of the bootstrap loader should be set to Mode 1 (8-bit UART, variable
baud rate) for communication. Timer 2 is in auto-reload mode (16-bit timer) for baud rate
measurement. A test byte (80
reception of the start bit (0) and stopping it on reception of the last bit of the test byte (1).
From the captured timer value, the bootstrap loader calculates the actual baud rate and
activates Timer 2 as the baud rate generator of the serial interface.
synchronization is done, the bootstrap loader sends back the Acknowledge byte (55
to the host and enter phase II. If the communication is not established due to difference
in the actual and calculated baudrate, a reset to the C868 has to be activated to restart
the device for a new synchronization attempt.
User’s Manual
(asynchronous, 8N1)
Host Computer
Serial Interface
PC
Phase I: Automatic Serial Synchronization to the Host
Bootstrap Loader Interface to the PC
H
) from the host
H
) from the host is captured by starting the timer on
full duplex, RS232
H
Serial Cable
) to the host
9-6
(asynchronous, 8N1)
Serial Interface,
UART Mode 1
The Bootstrap Loader
C868
V 1.0, 2003-01
When the
C868
H
)