71M6543F Maxim, 71M6543F Datasheet - Page 56

• Manufacturer Part Number: 71M6543F
• Description: The 71M6543F/71M6543H are Teridian's 4th-generation polyphase metering system-on-chips (SoCs) with a 5MHz, 8051-compatible MPU core, low-power real-time clock (RTC) with digital temperature compensation, flash memory, and LCD driver
• Manufacturer: Maxim

71M6543F/H and 71M6543G/GH Data Sheet
Table 46
2.5.6 71M6xx3 Temperature Sensor
56
TBYTE_BUSY
TEMP_PER[2:0]
TEMP_BAT
TEMP_START
TEMP_PWR
TEMP_BSEL
TEMP_TEST[1:0] 2500[1:0]
STEMP[10:3]
STEMP[2:0]
BSENSE[7:0]
BCURR
Name
measurement may not finish. In this case, firmware may complete the measurement by selecting
V3P3D (TEMP_PWR = 1).
If TEMP_PWR selects VBAT_RTC when the battery is nearly discharged, the temperature
shows the I/O RAM registers used for temperature and battery measurement.
Table 46: I/O RAM Registers for Temperature and Battery Measurement
28A0[2:0]
Location
2881[7:0]
2882[7:5]
2885[7:0]
28A0[3]
28A0[4]
28B4[6]
28A0[6]
28A0[7]
2704[3]
© 2008–2011 Teridian Semiconductor Corporation
Rst
0
0
0
0
0
0
0
–
0
Wk
0
–
–
–
–
–
–
–
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Dir
R
R
R
R
Indicates that hardware is still writing the 0x28A0
byte. Additional writes to this byte are locked out
while it is one. Write duration could be as long as 6 ms.
Sets the period between temperature measurements.
Automatic measurements can be enabled in any
mode (MSN, BRN, LCD, or SLP).
Causes VBAT to be measured whenever a
temperature measurement is performed.
TEMP_PER[2:0] must be zero in order for TEMP_START
to function. If TEMP_PER[2:0] = 0, then setting
TEMP_START starts a temperature measurement.
Ignored in SLP and LCD modes. Hardware clears
TEMP_START when the temperature measurement is
complete.
Selects the power source for the temperature sensor:
1 = V3P3D, 0 = VBAT_RTC. This bit is ignored in
SLP and LCD modes, where the temperature sensor is
always powered by VBAT_RTC.
Selects which battery is monitored by the
temperature sensor: 1 = VBAT, 0 = VBAT_RTC
Test bits for the temperature monitor VCO.
TEMP_TEST must be 00 in regular operation. Any
other value causes the VCO to run continuously with
the control voltage described below.
The result of the temperature measurement.
The STEMP[10:0] value may be obtained in C with a
single 16-bit read and divide by 32 operation as
follows:
volatile int16_t xdata STEMP _at_0x2881;
fa = (float)(STEMP/32);
The result of the battery measurement.
Connects a 100 µA load to the battery selected by
TEMP_BSEL.
Description
TEMP_PER
TEMP_TEST
1-6
1X
0
7
00
01
Time
Manual updates (see TEMP_START)
2 ^ (3+TEMP_PER) (seconds)
Continuous
Function
Normal operation
Reserved for factory test
Reserved for factory test
v1.2