71M6521BE
Energy Meter IC
DATA SHEET
JANUARY 2008
FLSHCRL
0xB2
R/W Bit 0 (FLSH_PWE): Program Write Enable:
0 – MOVX commands refer to XRAM Space, normal operation
(default).
1 – MOVX @DPTR,A moves A to Program Space (Flash) @
DPTR.
This bit is automatically reset after each byte written to flash. Writes
to this bit are inhibited when interrupts are enabled.
W
R/W
R
Bit 1 (FLSH_MEEN): Mass Erase Enable:
0 – Mass Erase disabled (default).
1 – Mass Erase enabled.
Must be re-written for each new Mass Erase cycle.
Bit 6 (SECURE):
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.
Bit 7 (PREBOOT):
Indicates that the preboot sequence is active.
WDI
0xE8
Only byte operations on the whole WDI register
should be used when writing. The byte must have all
bits set except the bits that are to be cleared.
R/W
R/W
The multi-purpose register WDI contains the following bits:
Bit 0 (IE_XFER): XFER Interrupt Flag:
This flag monitors the XFER_BUSY interrupt. It is set by hardware
and must be cleared by the interrupt handler
W
Bit 1: Reserved
Bit 7 (WD_RST): WD Timer Reset:
Read: Reads the PLL_FALL interrupt flag
Write 0: Clears the PLL_FALL interrupt flag
Write 1: Resets the watch dog timer
INTBITS
INT0…INT6
0xF8
R
Interrupt inputs. The MPU may read these bits to see the input to
external interrupts INT0, INT1, up to INT6. These bits do not have
any memory and are primarily intended for debug use
Table 11: Special Function Registers
Instruction Set
All instructions of the generic 8051 microcontroller are supported. A complete list of the instruction set and of the associated
op-codes is contained in the 71M6521 Software User’s Guide (SUG).
UART
The 71M6521BE includes a UART (UART0) that can be programmed to communicate with a variety of AMR modules. A
second UART (UART1) is connected to the optical port, as described in the optical port description.
The UART is a dedicated 2-wire serial interface, which can communicate with an external host processor at up to 38,400 bits/s
((with MPU clock = 1.2288MHz). The operation of each pin is as follows:
RX: Serial input data are applied at this pin. Conforming to RS-232 standard, the bytes are input LSB first.
TX: This pin is used to output the serial data. The bytes are output LSB first.
Page: 22 of 97
© 2005-2008 TERIDIAN Semiconductor Corporation
V1.0
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
