EM357-RTR datasheet(55/240 Pages) ETC2

55 / 240 page

EM351 / EM357

7.6.2

Input Mode

Input mode is used both for general purpose input and for on-chip peripheral inputs. Input floating mode

disables the internal pull-up and pull-down resistors, leaving the pin in a high-impedance state. Input pull-up

or pull-down mode enables either an internal pull-up or pull-down resistor based on the GPIO_PxOUT register.

Setting a bit to 0 in GPIO_PxOUT enables the pull-down and setting a bit to 1 enables the pull up.

When configured in input mode:

The output drivers are disabled.

An internal pull-up or pull-down resistor may be activated depending on GPIO_PxCFGH/L and GPIO_PxOUT.

The Schmitt trigger input is connected to the pin.

Reading GPIO_PxIN returns the input at the pin.

The input is also available to on-chip peripherals.

7.6.3

Output Mode

Output mode provides a general purpose output under direct software control. Regardless of whether an

output is configured as push-pull or open-drain, the GPIO’s bit in the GPIO_PxOUT register controls the

output. The GPIO_PxSET and GPIO_PxCLR registers can atomically set and clear bits within GPIO_PxOUT

to disable interrupts to perform an atomic read-modify-write operation of GPIO_PxOUT.

When configured in output mode:

The output drivers are enabled and are controlled by the value written to GPIO_PxOUT:

• In open-drain mode: 0 activates the N-MOS current sink; 1 tri-states the pin.

• In push-pull mode: 0 activates the N-MOS current sink; 1 activates the P-MOS current source.

The internal pull-up and pull-down resistors are disabled.

The Schmitt trigger input is connected to the pin.

Reading GPIO_PxIN returns the input at the pin.

Reading GPIO_PxOUT returns the last value written to the register.

Note:

Depending on configuration and usage, GPIO_PxOUT and GPIO_PxIN may not have the same value.

7.6.4

Alternate Output Mode

In this mode, the output is controlled by an on-chip peripheral instead of GPIO_PxOUT and may be configured

as either push-pull or open-drain. Most peripherals require a particular output type – TWI requires an open-

drain driver, for example – but since using a peripheral does not by itself configure a pin, the GPIO_PxCFGH/L

registers must be configured properly for a peripheral’s particular needs. As described in the Configuration

section, when more than one peripheral can be the source of output data, registers in addition to

GPIO_PxCFGH/L determine which to use.

When configured in alternate output mode:

The output drivers are enabled and are controlled by the output of an on-chip peripheral:

• In open-drain mode: 0 activates the N-MOS current sink; 1 tri-states the pin.

• In push-pull mode: 0 activates the N-MOS current sink; 1 activates the P-MOS current source.

The internal pull-up and pull-down resistors are disabled.

The Schmitt trigger input is connected to the pin.

Reading GPIO_PxIN returns the input to the pin.

Note:

Depending on configuration and usage, GPIO_PxOUT and GPIO_PxIN may not have the same value.

7-6

120-035X-000D

Preliminary

EM357-RTR 数据表(PDF) 55 Page - List of Unclassifed Manufacturers

EM357-RTR 数据表(HTML) 55 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载

链接网址

EM357-RTR 数据表(PDF) 55 Page - List of Unclassifed Manufacturers

EM357-RTR 数据表(HTML) 55 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表 下载

链接网址

数据表下载