ez80f92 ZiLOG Semiconductor, ez80f92 Datasheet - Page 97

• Manufacturer Part Number: ez80f92
• Description: Ez80acclaim Flash Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS015313-0508
Real-Time Clock Registers
•
•
The Real-Time Clock registers are accessed via the address and data bus using I/O instruc-
tions. RTC_UNLOCK controls access to the RTC count registers. When unlocked
(RTC_UNLOCK = 1), the RTC count is disabled and the count registers are Read/Write.
When locked (RTC_UNLOCK = 0), the RTC count is enabled and the count registers are
Read Only. The default, at RESET, is for the RTC to be locked.
Real-Time Clock Seconds Register
This register contains the current seconds count. The value in the RTC_SEC register is
unchanged by a RESET. The current setting of BCD_EN determines whether the values in
this register are binary (BCD_EN = 0) or binary-coded decimal (BCD_EN = 1). Access to
this register is Read Only if the RTC is locked and Read/Write if the RTC is unlocked. See
Table
Table 38. Real-Time Clock Seconds Register; (RTC_SEC = 00E0h)
Bit
Reset
CPU Access
Note: X = Unchanged by RESET; R/W* = Read Only if RTC locked, Read/Write if RTC unlocked.
Binary-Coded-Decimal Operation (BCD_EN = 1)
Bit
Position
[7:4]
TEN_SEC
[3:0]
SEC
Binary Operation (BCD_EN = 0)
Bit
Position
[7:0]
SEC
Write values to the RTC alarm registers to set the appropriate alarm conditions
Write to RTC_CTRL to clear the RTC_UNLOCK bit; clearing the RTC_UNLOCK bit
resets and enables the clock divider
38.
Value Description
0–5
0–9
Value Description
00h–
3Bh
R/W*
The tens digit of the current seconds count.
The ones digit of the current seconds count.
The current seconds count.
X
7
R/W*
X
6
R/W*
X
5
R/W*
X
4
R/W*
X
3
Product Specification
R/W*
X
2
Real-Time Clock
R/W*
X
1
R/W*
X
0
90