TMS370Cx36
8-BIT MICROCONTROLLER
SPNS039B – JANUARY 1996 – REVISED FEBRUARY 1997
45
POST OFFICE BOX 1443
HOUSTON, TEXAS 77251–1443
ADC1 converter (continued)
The ADC1 module allows complete freedom in design of the sources for the analog inputs. The period of the
sample time is user-defined so that the high-impedance can be accommodated without penalty to the
low-impedance sources. The sample period begins when the SAMPLE START bit of the ADC1 control register
(ADCTL.6) is set to 1. The end of the signal sample period occurs when the conversion bit (CONVERT START,
ADCTL.7) is set to 1. After a hold time, the converter will reset the SAMPLE START and CONVERT START bits,
signaling that a conversion has started and that the analog signal can be removed.
analog timing requirements (see Figure 22)
MIN
MAX
UNIT
tsu(S)
th(AN)
tw(S)
The value given is valid for a signal with a source impedance > 1 k
. If the source impedance is < 1 k
, use a minimum sampling time of 1
μ
s.
Setup time, analog to sample command
0
ns
Hold time, analog input from start of conversion
Pulse duration, sample time per kilo-
of source impedance
18tc
ns
1
μ
s/k
Analog In
Sample Start
Convert Start
Analog Stable
th(AN)
tw(S)
tsu(S)
Figure 22. Analog Timing
Table 19 is designed to aid the user in referencing a device part number to a mechanical drawing. The table
shows a cross-reference of the device part number to the TMS370 generic package name and the associated
mechanical drawing by drawing number and name.
Table 19. TMS370Cx36 Family Package Type and Mechanical Cross-Reference
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(mil pin spacing)
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MECHANICAL NAME
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(50-mil pin spacing)
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(CLCC)
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(PLCC)
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PLASTIC LEADED CHIP CARRIER
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TMS370C036AFNT
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TMS370C036AFNA
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CERAMIC LEADED CHIP CARRIER
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SE370C736AFZT