mcf5282 Freescale Semiconductor, Inc, mcf5282 Datasheet - Page 388

• Manufacturer Part Number: mcf5282
• Manufacturer: Freescale Semiconductor, Inc

GPTE
General Purpose Timer Modules (GPTA and GPTB)
The PORTTn data direction register controls the data direction of an input capture pin. External pin
conditions trigger input captures on input capture pins configured as inputs.
To configure a pin for input capture:
PORTTnDDR does not affect the data direction of an output compare pin. The output compare function
overrides the data direction register but does not affect the state of the data direction register.
To configure a pin for output compare:
Table 20-23
20-20
N
0
0
1
1
1
1
1
1
1
1
1
1
1. Clear the pin’s IOS bit in GPTIOS.
2. Clear the pin’s DDR bit in PORTTnDDR.
3. Write to GPTCTL2 to select the input edge to detect.
1. Set the pin’s IOS bit in GPTIOS.
2. Write the output compare value to GPTCn.
3. Clear the pin’s DDR bit in PORTTnDDR.
4. Write to the OMn/OLn bits in GPTCTL1 to select the output action.
DDR
0
1
0
1
0
1
0
1
0
1
0
1
1
shows how various timer settings affect pin functionality.
GPTIOS
1 (OC)
0 (IC)
X
X
0
0
0
0
0
1
1
1
4
disable
EDGx
[B:A]
0 (IC
<> 0
<> 0
<> 0
<> 0
X
d)
X
X
X
X
X
0
(3)
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
OMx/
OLx
<> 0
<> 0
Table 20-23. GPT Settings and Pin Functions
0
X
X
X
X
X
X
X
X
0
5
2
OC3Mx
X
X
0
0
0
0
1
1
0
0
0
0
3
Data
Out
Out
Out
Out
Out
Out
Out
Pin
Dir.
In
In
In
In
In
OC action Output compare Pin readable only if DDR = 0
OC action Output compare Pin driven by OC action
Data reg.
Data reg.
Data reg.
Data reg.
Data reg.
Driven
Ext.
Ext.
Ext.
Ext.
Ext.
Pin
by
Digital output
Digital output
Digital output
Digital output
Digital output
Digital input
Digital input
Digital input
digital input
digital input
Function
IC and
IC and
Pin
GPT disabled by GPTEN = 0
GPT disabled by GPTEN = 0
Input capture disabled by EDGn
setting
Input capture disabled by EDGn
setting
Normal settings for input capture
Input capture of data driven to output
pin by CPU
OC3M setting has no effect because
IOS = 0
OC3M setting has no effect because
IOS = 0; input capture of data driven
to output pin by CPU
Output compare takes place but
does not affect the pin because of
the OMn/OLn setting
Output compare takes place but
does not affect the pin because of
the OMn/OLn setting
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