ZBasic Language Reference
16
ZBasic Microcontrollers
Option HeapLimit <constant-expression>
Default: n/a
This directive provides a different way of allocating RAM between the string heap and the task stacks.
The value provided is interpreted as a RAM address and specifies the limit beyond which the heap will
not grow. This directive is perhaps more useful with target devices that support external RAM. See the
section on setting heap and task stack sizes for more information.
Option MainTaskStackSize <constant-expression>
Default: n/a
This directive provides a different way of allocating RAM between the string heap and the task stacks.
The value provided is interpreted as the desired size of the task stack for the Main() task and the heap
limit is set at the end of the task stack. See the section on setting heap and task stack sizes for more
information.
Option TxQueueSize <constant-expression>
Default: 25
Option RxQueueSize <constant-expression>
Default: 50
These directives can be used to modify the sizes of the default transmission and reception queues for the
console channel (typically Com1). They are effective only for native mode devices such as the ZX-24n
and generic target devices. The value of zero for one or the other is useful for setting up the console for
transmit-only or receive-only operation.
Example
Option TxQueueSize 100
Option ConsoleSpeed [ <constant-expression> | Default ]
Default: see text
This directive can be used to set the default speed of the serial channel assigned to the console (typically
Com1 but see Option Console). It is not supported on VM devices with a VM version older than v3.0.4
nor is it supported on any ZX device based on the mega32. The set of allowable baud rates is given in
the table below; the shaded entries are supported only on native mode devices.
300
600
1200
2400
4800
9600
14400
19200
28800
38400
57600
76800
115200
230400
It is important to note that for VM devices, the speed selection is made part of the download image and is
written to Persistent Memory when the code is downloaded. If, later, a program is downloaded that does
not contain Option ConsoleSpeed directive, the Persistent Memory location containing the console speed
indicator will be unchanged from the earlier setting.
The default console speed is 19200 for all ZX devices and it is zero for all generic target devices. For
native mode devices, the console speed can be set to zero thereby requesting that the console serial
channel not be open initially. In this case, if you want to use the console serial channel you must
specifically open it. For ZX devices, setting the console speed to zero when Com1 is the console has the
further effect of allowing Com1 to be fully closed when CloseCom() is called. This is in contrast to the
normal ZX behavior of always keeping Com1 open. The primary advantage to specifying the speed as
zero is that it results in a smaller executable size provided that your application does not explicitly open
the console serial channel.
 |
 |
 |