Datasheet
         71M6521DE/DH/FE Data Sheet 
Page: 80 of 107    Rev 3   
RTC_DEC_SEC 
RTC_INC_SEC 
201C[1] 
201C[0] 
0 
0 
0 
0 
W 
RTC time correction bits. Only one bit may be pulsed at a time. 
When pulsed, causes the RTC time value to be incremented (or 
decremented) by an additional second the next time the RTC_SEC 
register is clocked. The pulse width may be any value. If an 
additional correction is desired, the MPU must wait 2 seconds 
before pulsing one of the bits again. Each write to one of these bits 
must be preceded by a write to 201F (WE). 
RTM_E 
2002[3] 
0 
0 
R/W 
Real Time Monitor enable. When ‘0’, the RTM output is low. This 
bit enables the two wire version of RTM 
RTM0[7:0] 
RTM1[7:0] 
RTM2[7:0] 
RTM3[7:0] 
2060 
2061 
2062 
2063 
0 
0 
0 
0 
0 
0 
0 
0 
R/W 
Four RTM probes. Before each CE code pass, the values of these 
registers are serially output on the RTM pin. The RTM registers are 
ignored when RTM_E=0. 
SECURE 
SFRB2[6] 
0 
-- 
R/W 
Enables security provisions that prevent external reading of flash 
memory and CE program RAM. This bit is reset on chip reset and 
may only be set. Attempts to write zero are ignored. 
SLEEP 
20A9[6] 
0 
0 
W 
Takes the 6521DE/DH/FE to sleep mode. Ignored if system power 
is present. The part will wake when the autowake timer times out, 
when push button is pushed, or when system power returns. 
SUM_CYCLES[5:0] 
2001[5:0] 
0 
0 
R/W 
The number of pre-summer outputs summed in the final summer.  
TMUX[4:0] 
20AA[4:0] 
2 
-- 
R/W 
Selects one of 32 signals for TMUXOUT. 
[4:0] 
Selected Signal 
[4:0] 
Selected Signal 
0x00  
DGND (analog) 
0x01  
Reserved 
0x02 
Reserved 
0x03 
Reserved 
0x04 
Reserved 
0x05 
Reserved 
0x06 
VBIAS (analog) 
0x07 
Not used 
0x08 
Reserved 
0x09 
Reserved 
0x0A 
Reserved 
0x0B 
-0x13  
Reserved 
0x14 
RTM (Real time 
output from CE) 
0x15  
WDTR_E, comparator 1 
Output AND V1LT3) 
0x16 – 
0x17 
Not used 
0x18 
RXD, from optical in-
terface, after optional 
inversion 
0x19 
MUX_SYNC 
0x1A 
CK_10M 
0x1B 
CK_MPU 
0x1C  
Reserved 
0x1D 
RTCLK_2P5 
0x1E 
CE_BUSY 
0x1F 
XFER_BUSY 
TRIM[7:0] 
20FF  0  0  R/W 
Contains TRIMT[7:0], TRIMBGA,TRIMBGB or TRIMM[2:0] depending 
on the value written to TRIMSEL[3:0]. If TRIMBGB = 0, the device is 
a 71M6521DE/FE, else it is a 71M6521DH. 
TRIMSEL[3:0] 
20FD[3:0]  0  0  R/W 
Selects the temperature trim fuse to be read with the TRIM 
register: 
TRIMSEL[3:0] 
Trim Fuse 
Purpose 
1 
TRIMT[7:0] 
Trim for the magnitude of 
VREF 
4 
TRIMM[2:0] 
Trim values related to 
temperature compensation 
5 
TRIMBGA 
6 
TRIMBGB 










