71M6533 Datasheet, PDF (42/124 Pages) Teridian Semiconductor Corporation – Energy Meter IC

71M6533/71M6534 Data Sheet
FDS_6533_6534_004
When not needed for the optical UART, the OPT_TX pin can alternatively be configured as DIO2,
WPULSE, or VARPULSE. The configuration bits are OPT_TXE[1:0]. Likewise, OPT_RX can alternately
be configured as DIO_1. Its control is OPT_RXDIS.
from
OPT_TX UART
A
OPT_TXINV
A
OPT_TXMOD
OPT_FDC
OPT_TXMOD = 0
VARPULSE 3
Internal
WPULSE 2
MOD
EN DUTY
DIO2 1
B0
OPT_TXE[1:0]
2
A
OPT_TXMOD = 1,
OPT_FDC = 2 (25%)
OPT_TX
B
B
V3P3
Figure 8: Optical Interface
1/38kHz
In the 71M6534, a multiplexer allows the selection of alternate pins DIO18/MTX and DIO22/RTX for
UART1. This function is controlled with the I/O RAM registers UMUX_E and UMUX_SEL.
1.4.7 Digital I/O
The device includes up to 40 pins (71M6533) or 53 pins (71M6534) of general purpose digital I/O. These
pins are compatible with 5 V inputs (no current limiting resistors are needed). The Digital I/O pins can be
categorized as follows:
• Dedicated DIO pins (5 pins): DIO3, DIO56, DIO57, DIO58, PB
• DIO/LCD segment pins
o A total of 33 pins for the 71M6533:
DIO4/SEG24 - DIO11/SEG31 (8 pins)
DIO13/SEG33 - DIO21/SEG41 (9 pins)
DIO23/SEG43 – DIO27/SEG47 (5 pins)
DIO29/SEG49 - DIO30/SEG50 (2 pins)
DIO41/SEG61 (1 pin)
DIO43/SEG63 - DIO45/SEG65 (3 pins)
DIO47/SEG67 – DIO51/SEG71 (5 pins)
o A total of 46 pins for the 71M6534:
DIO4/SEG24 – DIO30/SEG50 (27 pins)
DIO36/SEG56 – DIO39/SEG59 (4 pins)
DIO41/SEG61 – DIO55/SEG75 (15 pins)
• DIO pins combined with other functions (2 pins): DIO2/OPT_TX, DIO1/OPT_RX
On reset or power-up, all DIO pins are inputs until they are configured for the desired direction under
MPU control. The pin function can be configured by the I/O RAM registers LCD_BITMAPn. Setting
LCD_BITMAPn = 1 configures the pin for LCD, setting LCD_BITMAPn = 0 configures it for DIO.
Once a pin is configured as DIO, it can be configured independently as an input or output with the
DIO_DIR bits or the LCD_SEGn registers. Input and output data are written to or read from the pins using
SFR registers P0, P1, and P2.
Table 39 shows all the DIO pins with their configuration, direction control and data registers. Table en-
tries marked with an asterisk and grayed are applicable to the 71M6534 only.
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