DS12887A Datasheet, PDF (7/19 Pages) Maxim Integrated Products – Real-Time Clock

DS5000(T)
PARALLEL PROGRAM LOAD CYCLES Table 1
MODE
Program
Security Set
Verify
Prog Expanded
Verify Expanded
Prog MCON or Key registers
Verify MCON registers
RST PSEN PROG EA
1
0
0
V_PP
1
0
0
V_PP
1
X
X
1
1
0
0
V_PP
1
0
1
1
1
0
0
V_PP
1
0
1
1
P2.7
1
1
0
0
0
0
0
P2.6
0
1
0
1
1
1
1
P2.5
X
X
X
0
0
1
1
The Parallel Program Cycle is used to load a byte of
data into a register or memory location within the
DS5000(T). The Verify Cycle is used to read this byte
back for comparison with the originally loaded value to
verify proper load ing. The Security Set Cycle may be
used to enable and the Software Security feature of the
DS5000(T). One may also enter bytes for the MCON
register or for the five encryption registers using the Pro-
gram MCON cycle. When using this cycle, the absolute
register address must be presented at Ports 1 and 2 as
in the normal program cycle (Port 2 should be 00H). The
MCON contents can likewise be verified using the Verify
MCON cycle.
When the DS5000(T) first detects a Parallel Program
Strobe pulse or a Security Set Strobe pulse while in the
Program Load Mode following a Power–On Reset, the
internal hardware of the DS5000(T) is initialized so that
an existing 4K byte program can be programmed into a
DS5000(T) with little or no modification. This initializa-
tion automatically sets the Range Address for 8K bytes
and maps the lowest 4K byte bank of Embedded RAM
as program memory. The next 4K bytes of Embedded
RAM are mapped as Data Memory.
In order to program more than 4K bytes of program
code, the Program/Verify Expanded cycles can be
used. Up to 32K bytes of program code can be entered
and verified. Note that the expanded 32K byte Program/
Verify cycles take much longer than the normal 4K byte
Program/Verify cycles.
A typical parallel loading session would follow this pro-
cedure. First, set the contents of the MCON register
with the correct range and partition only if using expand-
ed programming cycles. Next, the encryption registers
can be loaded to enable encryption of the program/data
memory (not required). Then, program the DS5000(T)
using either normal or expanded program cycles and
check the memory contents using Verify cycles. The
last operation would be to turn on the security lock fea-
ture by either a Security Set cycle or by explicitly writing
to the MCON register and setting MCON.0 to a 1.
021998 7/19