Z8673312PSG Datasheet, PDF (63/84 Pages) Zilog, Inc. – CMOS Z8 OTP Microcontrollers

CMOS Z8^® OTP Microcontrollers
Product Specification
59
SMR (Fh) 0B
D7 D6 D5 D4 D3 D2 D1 D0
SCLK/TCLK Divide-by-16
0 OFF**
1 ON
External Clock Divide-by-2
0 SCLK/TCLK = XTAL/2*
1 SCLK/TCLK = XTAL
STOP-Mode Recovery Source
000 POR Only and/or External Reset*
001 P30
010 P31
011 P32
100 P33
101 P27
110 P2 NOR 0-3
111 P2 NOR 0-7
Stop Delay
0 OFF
1 ON
Stop Recovery Level
0 Low*
1 High
Stop Flag (Read only)
0 POR*
1 Stop Recovery
* Default setting after RESET
** Default setting after RESET and STOP-Mode Recovery
Figure 31. Stop Mode Recovery Register (Write-Only Except Bit D7, Which Is Read-Only)
SCLK/TCLK Divide-by-16 Select (D0). This bit of the SMR controls a divide-by-16
prescaler of SCLK/TCLK. The purpose of this control is to selectively reduce device
power consumption during normal processor execution (SCLK control) and/or HALT
mode (where TCLK sources counter/timers and interrupt logic).
External Clock Divide-by-Two (D1). This bit can eliminate the oscillator divide-by-two
circuitry. When this bit is 0, the System Clock (SCLK) and Timer Clock (TCLK) are equal
to the external clock frequency divided by two. The SCLK/TCLK is equal to the external
clock frequency when this bit is set (D1=1). Using this bit together with D7 of PCON fur-
ther helps lower EMI (that is, D7 (PCON) = 0, D1 (SMR) = 1). The default setting is zero.
Stop Mode Recovery Source (D2, D3, and D4). These three bits of the SMR register
specify the wake up source of the Stop Mode Recovery (Figure 32). Table 22 shows the
SMR source selected with the setting of D2 to D4. P33-P31 cannot be used to wake up
PS022901-0508
Electrical Characteristics