TK18 is embedded with 8051, its timer/counter and UART are compatible with 8051. However, TK18 has its particular peripheral functions namely Touch Key, ADC, PWM, I²C slave, LED driver and multi-function GPIOs. Note: please refer to Chapter 1 from TK18 Data Sheet for details.

Normal Operating Range:

Note: Please refer to Chapter 17 from TK18 Data Sheet for details.

There is an internal RESET module. Whether or not to reset is solely depending on the internal module, thus an external pin for Reset is unnecessary.

Note: Please refer to Chapter 5 of TK18 datasheet for details.

There are two internal RC oscillators as the clock source of processor. Therefore external oscillator is unnecessary.

Note: Please refer to Chapter 4 of TK18 data sheet for details.

After TK18 is reset, values for related memory is:

• IRAM value is not fixed (User need to reset the value before start using)
• XRAM value is not fixed (User need to reset the value before start using)
• Registers value will be reset to the system default
• Value of Flash memory stays unchanged (same as the value before reset)

TK18 LED module is an independent hardware, characteristics are:

• Maximum 7 COM x 8 SEG (56) hardware common cathode LED drivers
• Independent hardware with digital display register and scanning driver. User only needs to store display data into display register and LED hardware will scan COM and SEG ports automatically to initiate LED module. No driver is required.
• Able to configure LED hardware scan cycle and duty cycle
• COM0~COM5 are capable of driving strong current that will drive LED directly. No external crystal is required.

Note：Refer to Chapter 13 of TK18 data sheet for details.

TK18 UART supports standard 8051 UART hardware and registers.

Note: refer to Chapter 14 of TK18 data sheet for details.

SCON2 and SCON3 compose 16 bit counter to configure Baude rate of UART in operation Mode 2 & 3.

Refer to SCON2 and SCON3 in Chapter 14.3 of TK18 data sheet for details.

This timer/counter also supports original T0 and T1 in standard 8051 core and the only difference is that beside FSYS, T0 & T1 can also use 1μS as clock source. This 1µS pulse is a unique design in TK18, and let users can conveniently calculate the timing of T0 and T1.

Note: Refer to Chapter 9 of TK18 data sheet for details.

Since TK18 has 4 PWM output ports that are multiplexed with 4 GPIO respectively (that is PWM3/GPIO27, PWM2/GPIO26, PWM1/GPIO25 and PWM0/GPIO24), related GPIOD initial values will also decide the voltage level status of PWM output.

Refer to Chapter 11.4 of Tk18 data sheet for details.