User guide

9.6.1 TOY Clock Timekeeping Registers

CPU Address: 0x1C0100000 - 0x1C01FFFE0

Nbus offset: 0x8000 - 0xFFFF

Time information is contained in eight 8-bit read/write registers offset from the

base address:

Table 9–13 TOY Clock Timekeeping Registers

Field Register Description

<0:3> TOY_BASE_ADDR+00 0.00 sec

<4:7> 0.0 sec

<0:6> TOY_BASE_ADDR+01 Second

<0:6> TOY_BASE_ADDR+02 Minute

<0:5> TOY_BASE_ADDR+04 Hour

<0:3> TOY_BASE_ADDR+06 Day

<0:5> TOY_BASE_ADDR+08 Date

<0:4> TOY_BASE_ADDR+09 Month

<0:7> TOY_BASE_ADDR+0A Year

These registers are also used to control the following:

Field Register Description

<6> TOY_BASE_ADDR+04 Speciﬁes the format of the Hour unit. When clear,

hours are stored as BCD from 0x00 to 0x23. When

set, the format is 12-hour, that is, the hours are 01

to 12.

<5> Used with <6>=1. When clear, hours are AM. When

set, hours are PM.

<6> TOY_BASE_ADDR+09 Enable Square Wave

Enables/disables the ﬁxed-frequency square wave

output. When clear, the wave output is enabled

and can be used as the heartbeat interval timer

interrupt delivered through the interrupt register

2<5>.

Nbus 9–23