Motorola DSP56301 user manual Timer Control/Status Register TCSR0$FFFF8F Read/Write

Programming Sheets

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Sheet 2 of 3

Timers

Inverter Bit 8

0= 0- to-1 transitions on TIO input increment the counter, or high pulse width measured, or high pulse output on TIO

1= 1-to-0 transitions on TIO input increment the counter, or low pulse width measured, or low pulse output on TIO

Timer Reload Mode Bit 9

0 = Timer operates as a free running counter

1 = Timer is reloaded when selected condition occurs

Direction Bit 11

0 = TIO pin is input

1 = TIO pin is output

Data Input Bit 12

0 = Zero read on TIO pin

1 = One read on TIO pin

Data Output Bit 13

0 = Zero written to TIO pin

1 = One written to TIO pin

Prescaled Clock Enable Bit 15

0 = Clock source is CLK/2 or TIO

1 = Clock source is prescaler output

Timer Compare Flag Bit 21

0 = “1” has been written to TCSR(TCF), or timer compare interrupt serviced

1 = Timer Compare has occurred

Timer Overflow Flag Bit 20

0 = “1” has been written to TCSR(TOF), or timer Overflow interrupt serviced

1 = Counter wraparound has occurred

Timer Control Bits 4–7 (TC[3–0])

TC (3:0)	TIO	Clock		Mode
0000	GPIO	Internal		Timer
0001	Output	Internal		Timer Pulse
0010	Output	Internal		Timer Toggle
0011	Input	External		Event Counter
0100	Input	Internal		Input Width
0101	Input	Internal		Input Period
0110	Input	Internal		Capture
0111	Output	Internal		Pulse Width Modulation
1000	–		–	Reserved
1001	Output	Internal		Watchdog Pulse
1010	Output	Internal		Watchdog Toggle
1011	–		–	Reserved
1100	–		–	Reserved
1101	–		–	Reserved
1110	–		–	Reserved
1111	–		–	Reserved

Timer Enable Bit 0

0 = Timer Disabled

1 = Timer Enabled

Timer Overflow Interrupt Enable Bit 1

0 = Overflow Interrupts Disabled

1 = Overflow Interrupts Enabled

Timer Compare Interrupt Enable Bit 2

0 = Compare Interrupts Disabled

1 = Compare Interrupts Enabled

23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
*0	*0	TCF	TOF	*0	*0	*0	*0	PCE	*0	DO	DI	DIR	*0	TRM	INV	TC3	TC2	TC1	TC0	*0	TCIE	TQIE	TE
Timer Control/Status Register								TCSR0:$FFFF8F Read/Write
Reset = $000000								TCSR1:$FFFF8B Read/Write
								TCSR2:$FFFF87 Read/Write

*= Reserved, Program as 0

Figure B-26.Timer Control/Status Register (TCSR)

B-38 DSP56301 User’s Manual