nRF24E1 Nordic VLSI, nRF24E1 Datasheet - Page 70

• Manufacturer Part Number: nRF24E1
• Description: 2.4Ghz RF Transceiver With Embedded 8051 Compatible Microcontroller And 9 Input, 10 Bit ADC
• Manufacturer: Nordic VLSI

PRODUCT SPECIFICATION
The nRF24E1 includes three timer/counters (Timer 0, Timer 1 and Timer 2). Each
timer/counter can operate as either a timer with a clock rate based on the CPU clock ,
or as an event counter clocked by the t0 pin (Timer 0), t1 pin (Timer 1), or the t2 pin
(Timer 2). These pins are alternate function bits of Port 0 and 1 as this : t0 is P0.5, t1
is P0.6 and t2 is P1.0, for details please see ch. 3 I/O PORTS.
Each timer/counter consists of a 16-bit register that is accessible to software as three
SFRs: (Table 10-9 Special Function Registers)
Timers 0 and 1 each operate in four modes, as controlled through the TMOD SFR
(Table 10-13) and the TCON SFR (Table 10-14). The four modes are:
Bit
TMOD.7
TMOD.6
TMOD.5
TMOD.4
TMOD.3
TMOD.2
TMOD.1
TMOD.0
Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0
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Timer 0 - TL0 and TH0
Timer 1 - TL1 and TH1
Timer 2 - TL2 and TH2
13-bit timer/counter (mode 0)
16-bit timer/counter (mode 1)
8-bit counter with auto-reload (mode 2)
Two 8-bit counters (mode 3, Timer 0 only)
Function
GATE - Timer 1 gate control. When GATE = 1, Timer 1 will clock only when external
interrupt INT1_N = 1 and TR1 (TCON.6) = 1. When GATE = 0, Timer 1 will clock only
when TR1 = 1, regardless of the state of INT1_N.
C/T - Counter/Timer select. When C/T = 0, Timer 1 is clocked by CPU_clk/4 or
CPU_clk/12, depending on the state of T1M (CKCON.4). When C/T = 1, Timer 1 is clocked
by the t1 pin.
M1 - Timer 1 mode select bit 1.
M0 - Timer 1 mode select bit 0, decoded as:
GATE - Timer 0 gate control. When GATE = 1, Timer 0 will clock only when external
interrupt INT0_N = 1 and TR0 (TCON.4) = 1. When GATE = 0, Timer 0 will clock only
when TR0 = 1, regardless of the state of INT0_N.
C/T - Counter/Timer select. When C/T = 0, Timer 0 is clocked by CPU_clk/4 or
CPU_clk/12, depending on the state of T0M (CKCON.3). When C/T = 1, Timer 0 is clocked
by the t0 pin.
M1 - Timer 0 mode select bit 1.
M0 - Timer 0 mode select bit 0, decoded as:
M1 M0 Mode
M1 M0 Mode
00 Mode 0 : 13-bit counter
01 Mode 1 : 16-bit counter
10 Mode 2 : 8-bit counter with auto-reload
11 Mode 3 : Two 8-bit counters
00 Mode 0 : 13-bit counter
01 Mode 1 : 16-bit counter
10 Mode 2 : 8-bit counter with auto-reload
11 Mode 3 : Two 8-bit counters
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July 2003