sid-io-stdio (libconsoles.la :: console_component_library)

Synopsis:

This component performs input/output on the standard input/output.

Functionality:

Modelling:

This component acts as an interface between the host system's stdio streams and pins in the simulated system.

This component uses non-blocking I/O on the host. It cannot use blocking I/O because the entire simulation would block. As a result, this component requires time slices from the simulator to check for pending data that must be read from stdin. To do this, you can use a common scheduler component (sid-sched-*) to efficiently yield time to the sid-io-stdio component. However, you should carefully consider the choice of the time interval to be used by the scheduler. We recommend approximately 10 times per second.

Behaviors
output	When the stdout input pin is driven with a value between 0 and 255, the value is immediately written to stdout.
input	When the poll pin is driven, the stdin stream is checked for unread input, without blocking. All available input is consumed, and transmitted individually by driving the stdin pin with each byte, in sequence.

SID Conventions
functional	supported	-
save/restore	supported	null state save/restore.

Environment:

Related components

You can connect a stdio console to a serial data transmission component, such as a UART. You can also connect it to a ROM monitor/system call emulator, such as the sw-gloss-arm/angel which performs I/O across some sort of debug channel. In order for a stdio console component to collect data from standard input without blocking the entire simulation, non-blocking I/O is used. It is necessary to give simulation time to the component to collect any data from stdin and to buffer the data. To do this, you can use the common scheduler component (see Functionality, Modelling).

The following is an example of how a stdio console might be configured to connect into a system:

	new sid-sched-host sched
	new sw-gloss-arm/angel angel
	new sid-io-stdio stdio
	set sched enabled? 1
	set sched num-clients 1
	set sched 0-regular? 1
	set sched 0-time 50
	connect-pin sched 0-event -> stdio poll
	connect-pin angel debug-tx -> stdio stdout
	connect-pin angel debug-rx <- stdio stdin

Component Reference:

Component: sid-io-stdio

pins
name	direction	legalvalues	behaviors
poll	in	N/A	input
stdin	out	any character code	input
stdout	in	any character code	output

attributes
name	category	legal values	default value	behaviors
state-snapshot	-	opaque string	-	state save/restore