AN913 Datasheet, PDF (1/12 Pages) STMicroelectronics – PWM GENERATION WITH THE ST62 16-BIT AUTO-RELOAD TIMER

AN913
APPLICATION NOTE
PWM GENERATION WITH THE ST62
16-BIT AUTO-RELOAD TIMER
by 8-bit Micro Application Team
INTRODUCTION
This note presents how to use the ST62 16-bit Auto-Reload Timer (ARTimer) for generating a
DTMF signal (Dual-Tone Multiple Frequency) with the PWM. In the example shown, the PWM
output pin generates a DTMF to dial a telephone number.
1 16-BIT AUTO-RELOAD TIMER DESCRIPTION
This timer is a 16-bit downcounter timer with prescaler (see Figure 1.). It includes auto-reload
PWM, capture and compare capability with two input (CP1, CP2) and two output pins (OVF,
PWM). It is controlled by the following registers:
– Status control registers (8-bit) SCR1, SCR2, SCR3, SCR4
– CP Capture register pair (16-bits total): CPH and CPL
– MASK register pair (16-bits total): MASKH and MASKL
– TC 16-bit downcounter register
– CMP Compare register pair (16-bits total): CMPH and CMPL
– RLCP Reload/Capture register pair (16-bits total): RLCPH and RLCPL
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