ST10R272L - SYSTEM RESET
270/320
15.8
Internal RAM after reset
The contents of the internal RAM are not affected by a system resynchronized reset.
However, after a power-on reset, the contents of the internal RAM are undefined. This
implies that the GPRs (R15...R0) and the PEC source and destination pointers
(SRCP7...SRCP0, DSTP7...DSTP0) which are mapped into the internal RAM are also
unchanged after a warm reset, software reset or watchdog reset, but are undefined after a
power-on reset.
Note
Content of the internal RAM may be affected by a warm asynchronous reset.
15.9
Ports and external bus configuration during reset
During the internal reset sequence all of the ST10R272L’s port pins are configured as inputs
by clearing the associated direction registers, and their pin drivers are switched to the high
impedance state. This ensures that the ST10R272L and external devices will not try to drive
the same pin to different levels. Pin ALE is held low through an internal pulldown, and pins
RD and WR are held high through internal pullups. Also the pins selected for CS output will
be pulled high.
The registers SYSCON and BUSCON0 are initialized according to the configuration
selected via PORT0.Pin EA must be held at ‘0’ level.
•
Bus Type field (BTYP) in register BUSCON0 is initialized according to P0L.7 and P0L.6
•
bit BUSACT0 in register BUSCON0 is set to ‘1’
DPP3:
0003h (points to data page 3)
CP:
FC00h
STKUN:
FC00h
STKOV:
FA00h
SP:
FC00h
WDTCON:
0002h, if reset was triggered by a watchdog timer overflow, 0000h otherwise
S0RBUF:
XXh (undefined)
SSCRB:
XXXXh (undefined)
SYSCON:
0XX0h (set according to reset configuration)
BUSCON0:
0XX0h (set according to reset configuration)
RP0H:
XXh (reset levels of P0H)
ONES:
FFFFh (fixed value)
DPP1:
0001h (points to data page 1)