XA-H4 Datasheet, PDF (12/42 Pages) NXP Semiconductors – Single-chip 16-bit microcontroller

Philips Semiconductors
Single-chip 16-bit microcontroller
Preliminary specification
XA-H4
Name
Description
SFR
Address _MSB
Bit Functions and Addresses
Reset
LSB ^Value
TSTAT* Timer 0/1 Extended Status 411h
28F
28E
28D
28C
28B
28A
289
288
–
–
–
–
–
T1OE
–
T0OE 00h
2FF
2FE
2FD
2FC
2FB
2FA
2F9
2F8
WDCON* Watchdog Control
41Fh
PRE2 PRE1 PRE0
–
– WDRUN WDTOF –
6
WDL
Watchdog Timer Reload 45Fh
00h
WFEED1 Watchdog Feed 1
45Dh
x
WFEED2 Watchdog Feed 2
45Eh
x
NOTES:
* SFRs marked with an asterisk (*) are bit addressable.
# SFRs marked with a pound sign (#) are additional SFR registers specific to the XA-H3 and XA-H4.
1. The XA-H4 implements an 8-bit SFR bus, as stated in Chapter 8 of the IC25 Data Handbook XA User Guide. All SFR accesses must be
8-bit operations. Attempts to write 16 bits to an SFR will actually write only the lower 8 bits. 16-bit SFR reads will return undefined data in
the upper byte.
2. SFR is loaded from the reset vector.
3. F1, F0, and P reset to “0”. All other bits are loaded from the reset vector.
4. Unimplemented bits in SFRs are “X” (unknown) at all times. “1”s should not be written to these bits since they may be used for other
purposes in future XA derivatives. The reset value shown for these bits is “0”.
5. Port configurations default to quasi-bidirectional when the XA begins execution after reset. Thus all PnCFGA registers will contain FFh and
PnCFGB register will contain 00h. See warning in XA-H4 User Manual about P3.2_Timer0_ResetOut pin during first 258 clocks after power up.
Basically, during this period, this pin may output a strongly-driven low pulse. If the pulse does occur, it will terminate in a transition to high at a
time no later than the 259th system clock after valid V_CC power up.
6. The WDCON reset value is E6 for a Watchdog reset; E4 for all other reset causes.
7. The RSTSRC register reflects the cause of the last XA reset. One bit will be set to “1”, the others will be “0”. RSTSRC[7] enables the ResetOut
function; “1” = Enabled, “0” = Disabled. See XA-H4 User Manual for details; RSTSRC[7] differs in function from most other XA derivatives.
8. The XA guards writes to certain bits (typically interrupt flags) that may be written by a peripheral function. This prevents loss of an interrupt or
other status if a bit was written directly by a peripheral action between the read and write of an instruction that performs a read-modify-write
operation. XA-H4 SFR bits that are guarded in this manner are: TF1, TF0, IE1, and IE0 (in TCON), and WDTOF (in WDCON).
1999 Sep 24
12