The programming steps for the TTC are listed in Table: TTC Initialization through Table: TTC Stop Timer. This Figure shows the TTC flowchart.
Table 14-6: TTC Initialization
|
Task
|
Register
|
Register Field
|
Register Offset
|
Bits
|
Value
|
|
Check if timer counter is started
|
counter_control
|
DIS
|
0x0C
|
0
|
Read operation
|
|
Ensure timer counter has not started
|
|
Write reset value to the counter control register
|
counter_control
|
All
|
0x0C
|
31:0
|
0x21 (hex)
|
|
Reset clock control
|
clock_control
|
All
|
0x00
|
31:0
|
0x00 (hex)
|
|
Reset interval count value
|
interval_counter
|
All
|
0x24
|
31:0
|
0x00 (hex)
|
|
Reset match-1 value
|
match_1_counter
|
All
|
0x3C
|
31:0
|
0x00 (hex)
|
|
Reset match-2 value
|
match_2_counter
|
All
|
0x48
|
31:0
|
0x00 (hex)
|
|
Reset IER
|
interrupt_enable
|
All
|
0x60
|
31:0
|
0x00 (hex)
|
|
Reset ISR
|
interrupt_register
|
All
|
0x54
|
31:0
|
0x00 (hex)
|
|
Reset counter
|
counter_control
|
RST
|
0x0C
|
4
|
1b'1
|
Table 14-7: TTC Set Options
|
Task
|
Register
|
Register Field
|
Register Offset
|
Bits
|
Value
|
|
External clock set option
|
clock_control
|
C_Src
|
0x00
|
5
|
1b'1
|
|
External clock deselect option
|
clock_control
|
C_Src
|
0x00
|
5
|
1b'0
|
|
Negative edge clock selection
|
clock_control
|
Ex_E
|
0x00
|
6
|
1b'1
|
|
Negative edge clock deselect
|
clock_control
|
Ex_E
|
0x00
|
6
|
1b'0
|
|
Interval mode select
|
counter_control
|
INT
|
0x0C
|
1
|
1b'1
|
|
Interval mode deselect
|
counter_control
|
INT
|
0x0C
|
1
|
1b'0
|
|
Decrement counter
|
counter_control
|
DEC
|
0x0C
|
2
|
1b'1
|
|
Decrement counter deselect
|
counter_control
|
DEC
|
0x0C
|
2
|
1b'0
|
|
Select match mode
|
counter_control
|
Match
|
0x0C
|
3
|
1b'1
|
|
Deselect match mode
|
counter_control
|
Match
|
0x0C
|
3
|
1b'0
|
|
Disable waveform output
|
counter_control
|
Wave_en
|
0x0C
|
5
|
1b'1
|
|
Enable waveform output
|
counter_control
|
Wave_en
|
0x0C
|
5
|
1b'0
|
|
Select waveform polarity
|
counter_control
|
Wave_pol
|
0x0C
|
6
|
1b'0
|
|
Select waveform polarity
|
counter_control
|
Wave_pol
|
0x0C
|
6
|
1b'0
|
Table 14-8: TTC Set Prescaler
|
Task
|
Register
|
Register Field
|
Register Offset
|
Bits
|
Value
|
|
Clear prescaler control bits
|
clock_control
|
PS_V | PS_En
|
0x00
|
4:0
|
5b'00000
|
|
Write the value only if prescaler value is less than 16
|
clock_control
|
PS_V | PS_En
|
0x00
|
4:0
|
Prescaler value to
be written
|
Table 14-9: Setup Timer
|
Task
|
Register
|
Register Field
|
Register Offset
|
Bits
|
Value
|
|
Stop timer
|
counter_control
|
DIS
|
0x0C
|
0
|
1b'1
|
|
Initialize the device. Refer to TTC Initialization.
|
|
Set required options. Refer to TTC Set Options.
|
|
Calculate interval and prescaler.
|
|
Setup interval
|
interval_counter
|
All
|
0x24
|
31:0
|
Interval value calculated in previous step
|
|
Set prescaler value calculated in previous step. Refer to TTC Set Prescaler.
|
Table 14-10: Setup Ticker
|
Task
|
Register
|
Register Field
|
Register Offset
|
Bits
|
Value
|
|
Setup timer. Refer to Setup Timer.
|
|
Register the ticker handler with the GIC.
|
|
Enable TTC interrupts in the GIC.
|
|
Enable interval interrupt
|
interval_counter
|
Interval
|
0x60
|
0
|
1b'1
|
|
Start timer
|
counter_control
|
DIS
|
0x0C
|
0
|
1b'0
|
Table 14-11: TTC Stop Timer
|
Task
|
Register
|
Register Field
|
Register Offset
|
Bits
|
Value
|
|
Stop timer
|
counter_control
|
DIS
|
0x0C
|
0
|
1b'1
|