TC7109 View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
'TC7109' PDF : 30 Pages View PDF
TC7109/A
Integrator Output
Internal Clock
Internal Latch
Status Output
RUN/HOLD Input
Determinated at
Zero Crossing
Detection
Auto-Zero Phase I
Min 1790 Counts
Max 2041 Counts
Static in
Hold State
INT
Phase II
7 Counts
*
*Note: RUN/HOLD input is ignored until end of auto-zero phase.
FIGURE 3-3:
TC7109A RUN/HOLD Operation
3.2.4 DIRECT MODE
The data outputs (bits 1 through 8, low order bytes; bits
9 through 12, polarity and over range high order bytes)
are accessible under control of the byte and chip
enable terminals as inputs, with the MODE pin at a
LOW level. These three inputs are all active LOW.
Internal pull-up resistors are provided for an inactive
HIGH level when left open. When chip enable is LOW,
a byte enable input LOW will allow the outputs of the
byte to become active. A variety of parallel data
accessing techniques may be used, as shown in the
“Interfacing” section. (See Figure 3-4 and Table 3-1.)
The access of data should be synchronized with the
conversion cycle by monitoring the Status output. This
prevents accessing data while it is being updated and
eliminates the acquisition of erroneous data.
CE/LOAD
As Input
HBEN
As Input
LBEN
As Input
High Byte
Data
Low Byte
Data
tBEA
tCEA
tDAB
Data
Valid
tDAB
tDAC
= High-Impedance
Data
Valid
Data
Valid
tDHC
TABLE 3-1: TC7109A DIRECT MODE
TIMING REQUIREMENTS
Symbol
Description
Min Typ Max Units
tBEA
tDAB
tDHB
tCEA
tDAC
tDHC
Byte Enable Width
Data Access Time
from Byte Enable
Data Hold Time
from Byte Enable
Chip Enable Width
Data Access Time
from Chip Enable
Data Hold Time
from Chip Enable
200 500 — nsec
— 150 300 nsec
— 150 300 nsec
300 500
nsec
— 200 400 nsec
— 200 400 nsec
3.2.5 HANDSHAKE MODE
An alternative means of interfacing the TC7109A to
digital systems is provided when the Handshake Out-
put mode of the TC7109A becomes active in controlling
the flow of data, instead of passively responding to chip
and byte enable inputs. This mode allows a direct inter-
face between the TC7109A and industry standard
UARTs with no external logic required. The TC7109A
provides all the control and flag signals necessary to
sequence the two bytes of data into the UART and ini-
tiate their transmission in serial form when triggered
into the Handshake mode. The cost of designing
remote data acquisition stations is reduced using serial
data transmission to minimize the number of lines to
the central controlling processor.
FIGURE 3-4:
Output Timing
TC7109A Direct Mode
© 2006 Microchip Technology Inc.
DS21456C-page 11
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