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TMP92CZ26A
92CZ26A-45
3.4.3 Outline of Boot Operation
The method for downloading a user program can be selected from two types: from UART,
or via USB.
After reset, the boot program on the internal boot ROM executes as shown in
Figure 3.4.2.
Regardless of the downloading method used, the boot program downloads a user program
into the internal RAM and then branches to the internal RAM.
Figure 3.4.3 shows how the
boot program uses the internal RAM (common to all the downloading methods).
Note 1: To download a user program via USB, a USB device driver and special application software are needed on
the PC.
Note 2: To download a user program via UART, special application software is needed on the PC.
Note 3: The (a), (b) in the above flowchart indicate points where the settings of external port pins are changed. For
details, see
Table 3.4.3.
Figure 3.4.2 Flowchart for Internal Boot ROM Operation
Start
Branch to internal RAM
3000h
Yes
Clock setting
•
f
SYS
= f
OSCH
•
f
USB
= f
OSCH
× 24/5
(a)
UART
check
No
Yes
Download via UART
USB
check
Yes
Download via
USB
No
(b)
RESUME check
PMCCTL<PCM
_
ON>=1
Branch to internal RAM
46000h
No