16 16-BIT AUDIO PWM TIMER (T16P)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
16-13
6.3 Split Mode Selection
Table 16.
SPLTMD[1:0]
Split mode
0x3
10 bits + 6 bits split mode
0x2
9 bits + 7 bits split mode
0x1
8 bits + 8 bits split mode
0x0
16 bits normal mode
(Default: 0x0)
When a split mode is selected, the split high-order data bits (10, 9, or 8 high-order bits) and low-order
data bits (6, 7, or 8 low-order bits) are compared with the counter data and the two comparison results
generate two PWM output signals. The PWM signal generated from the high-order data bits is output
from the PWM_H pin and another generated from the low-order data bits is output from the PWM_L
pin. When a split mode or 8-bit PCM data resolution is selected, compare A interrupts cannot be gener-
ated.
Note: SPLTMD[1:0] does not affect 8-bit PCM data.
D7
Reserved
D6
SELFM: Fine Mode Select Bit
Sets T16P to fine mode.
1 (R/W): Fine mode
0 (R/W): Normal comparison mode (default)
In normal comparison mode, compare A data is compared with the counter data at the rising edge of the
count clock. When T16P is set to fine mode, the comparisons are performed at both rising and falling
edges of the count clock. At this time the compare A data is halved when compared.
Count clock (PCLK1)
Counter
PWM_H output in normal comparison mode
PWM_H output in fine mode
(Compare A data = 3, Compare B data = 5)
1
2
3
4
5
0
0
1
2
3
4
5
0
1
6.1 Fine Mode
Figure 16.
The fine mode improves the precision of the pulse width. Note, however, that the PCLK1/1 clock can
only be used as the count clock in this mode. CLKSEL and CLKDIV[3:0] settings are ineffective.
The fine mode does not affect the pulse period that is determined with compare B data.
Note: When using A match interrupts while T16P is placed into fine mode, the maximum value of
CMPB[15:0] is limited to 2
15
- 1 (= 32,767) and the CMPA[15:0] programmable range is limited
to 0 to (2 × CMPB[15:0] - 1).
However, there is no such limitation when T16P is used only for generating PWM pulses with
A match interrupt disabled.
D5
Reserved
D4
INITOL: Initial Output Level Select Bit
Selects the initial output level for the PWM_H and PWM_L outputs.
1 (R/W): High
0 (R/W): Low (default)
The PWM_H and PWM_L output pins go to the initial output level when the pin function is switched
for T16P before starting T16P or when T16P is stopped or reset. When INITOL is set to 0, the initial
output level is set to low. When INITOL is set to 1, the initial output level is set to high.
Note: Before the pin function is switched for T16P, be sure to set INITOL and then reset the T16P (set
PRESET to 1).