Sino Wealth SH61F83, Руководство пользователя

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SH61F83
34
8. Base Timer

The Timer-x is an 8-bit counter with a programmable clock source selection and the value of Base Timer-x counter can be
read out any time.(x = 0, 1)

The Base Timer-x can be enabled/disabled by the CPU. After reset, the Base Timer-x is disabled and cleared.

The Base Timer-x can be preset by writing a preset value to BTx register at any time. When the Base Timer-x is enabled,
the Base Timer-x starts counting from the preset value to FFH and when the values reaches 00H, it generates a Base
Timer-x interrupt if the Base Timer-x interrupt is enabled. When it reaches 00H, the Base Timer-x will auto-load the value in
BTx register and begins counting.

The Base Timer-x can be enabled by writing a “1” to “ ENBTx ” in the BTCON (Base Timer Control) register. The ENBTx is
level trigger. If any value is written to BTx register when it is counting, Base Timer-x will reload that value immediately and
continue counting from that written value. Every time ENBTx goes rising, the counter begins to count from the preset value
in BTx register.

The input clock source of Base Timer-x is controlled by the BTxM[2:0] register. The following table shows 8 ranges of the
Base Timer-x. For counting accuracy, please set the Base Timer-x register first, then preset the BTxM[2:0] register, last,
enable the Base Timer-x.
00D2H BT0 Initial Value Base Timer-0 Control Register
Bit[7:0] BT0[7:0] 00h R/W
Base Timer-0 register
Reset Source: Hardware reset or USB reset
00D3H BT1 Initial Value Base Timer-1 Control Register
Bit[7:0] BT1[7:0] 00h R/W
Base Timer-1 register
Reset Source: Hardware reset or USB reset
00D4H BTCON Initial Value Base Timer Control Register
Bit7 ENBT1 0b R/W
0: Disable Base Timer-1
1: Enable Base Timer-1
Reset Source: Hardware reset or USB reset
Bit[6:4] BT1M[2:0] 000b R/W
Base Timer-1 clock source
000: F
BT
/2
0
001: F
BT
/2
1
010: F
BT
/2
2
011: F
BT
/2
3
100: F
BT
/2
4
101: F
BT
/2
5
110: F
BT
/2
6
111: F
BT
/2
7
F
BT
= F
SYS
/6
Reset Source: Hardware reset or USB reset
Bit3 ENBT0 0b R/W
0: Disable Base Timer-0
1: Enable Base Timer-0
Reset Source: Hardware reset or USB reset
Bit[2:0] BT0M[2:0] 000b R/W
Base Timer-0 clock source
000: F
BT
/2
0
001: F
BT
/2
1
010: F
BT
/2
2
011: F
BT
/2
3
100: F
BT
/2
4
101: F
BT
/2
5
110: F
BT
/2
6
111: F
BT
/2
7
F
BT
= F
SYS
/6
Reset Source: Hardware reset or USB reset