8. TwinPEEKs Monitor
Software Version 2.3
Serial Communication
TwinPEEKs communicates over the first RS232 interface ("SER0",
X3) at
19200 Baud
. Settings are: 8N1, no hardware or software hand-
shake, no protocol.
Autostart Function
After reset, the TwinPEEKs monitor checks, whether port pins PE5
(MODA) and PE6 (MODB) are connected (X1B pins 1+2). If this is the
case, the monitor immediately jumps to address $8000.
This feature allows to start an application program automatically
without modifying the reset vector, which is located in the protected
Flash Boot Block.
Write Access to Flash and EEPROM
The CPU can read every single byte of the microcontroller's resour-
ces - the type of memory does not matter. However, for write accesses,
some rules have to be followed: Flash and EEPROM have to be erased
before any write attempt. Programming is done by writing words (two
bytes at a time) to aligned addresses.
To form such aligned words, two subsequent bytes have to be
combined. TwinPEEKs is aware of this, but the following problem can
not be avoided by the monitor:
The monitor is processing each S-Record line seperately. If the last
address of such an S-Record is even, the 2nd byte to form a complete
word is missing. TwinPEEKs will append an $FF byte in this case, so it
is able to perform the word write.
The problem occurs, if the byte stream continues with the follo-
wing S-Record line. The byte, that was missing in the first attempt,
S12compact
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