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Task s and Ki ts ProM aster 25 00 User Manua l 3-17 The value of YYYY YY YY is the address where the byte of data is s tored in the 2 500’s RAM. Relative Addr essing Under most circum stances the I/O Off set is left at i…

Tasks and Kits

3-16 ProMaster 2500 User Manual

There is one situation when the word width value would be changed.

This occurs if you are trying to program 16-bit RAM data into two 8-bit

memory devices. Assume that the 2500 loads a file intended to program

16-bit data into two 8-bit devices. The low order bytes of each 16-bit word

are saved to all even address in RAM beginning with RAM address 0

(zero). The high order bytes for each word would be stored at RAM

address 1 and all odd address locations. If the default parameters are not

changed, the 2500 would program an 8-bit device (without any errors)

with both odd and even bytes. The device would not operate in a 16-bit

data circuit.

To program all low order bytes into one 8-bit device and all the high

order bytes into the second 8-bit device, the word width should be set as

if it were one “virtual” 16-bit device. The two 8-bit devices will operate in

their target circuit application “virtually” as if they were a single 16-bit

device.

To program a virtual 16-bit device using two 8-bit parts, perform the

following steps:

1. Create two Tasks, one for each 8-bit device that downloads the same

16-bit data file. In the first Task, Set Word Width = 16 (see Figure

3-11), and Set Begin RAM = 0 (default).

2. Create a second Task exactly the same as the first except: Set Begin

RAM = 1.

3. Load the first Task.

4. Program the number of devices required. The combination of these

two parameters instructs the 2500 to program the device from all

even RAM addresses, beginning with address 0. This creates the low

order device in the two-device set.

5. Load the second Task.

6. Program the number of devices equal to the number programmed by

the first Task. The 2500 programs the second device from all odd

RAM addresses, beginning with RAM address 1. This creates the

high order device in the two device set.

Setting I/O Offset

I/O Offset is a value that is subtracted from each file address during a

data file download from the PC to the 2500’s RAM. During a data file

upload from the 2500’s RAM to a PC file, the I/O Offset value is added to

the RAM address before it is transmitted.

The following example uses a file download, because it is the most

common application.

File Download:

File address number

– I/O offset number

----------------------------------

XXXX XXXX

Beginning RAM address number

-----------------------------------------------------

2500 RAM address =

YYYY YYYY

Tasks and Kits

ProMaster 2500 User Manual 3-17

The value of

YYYY YYYY

is the address where the byte of data is stored

in the 2500’s RAM.

Relative Addressing

Under most circumstances the I/O Offset is left at its default value of

FFFFFFFF

. By default, the 2500 assumes that the first byte of data it

receives should be located at RAM address 0 and all other data bytes

received will be located in RAM at addresses relative to the address of the

first byte. During a data file download from the PC to the 2500, the

default value instructs the 2500 to take the first data byte in the file

(regardless of the address that byte has in the file) and save it at the 2500’s

RAM address = 0. The address of the first byte becomes the I/O Offset

value and is subtracted from all subsequent data file addresses to arrive

at the ultimate 2500 RAM address for that file data byte.

The sample below shows how this

relative

addressing works in a typical

application.

File Download:

File address number 800

– I/O offset number -800

---------------------------------- -----

XXXX XXXX

000

Begin RAM number +000

--------------------------------- -----

2500 RAM address =

YYYY YYYY

000

Absolute Addressing

This parameter is usually changed from the default during a file

download from the PC to 2500’s RAM. Some file formats (primarily the

Intel formats) use absolute addresses. In this context we mean that the

address of each data byte in the file is the absolute address and the data

byte associated with that address should be saved at the same address in

the 2500’s RAM. If your file uses absolute addressing, then the I/O Offset

should be set to 0.

The following example shows how this

absolute

addressing works in a

typical application.

File Download:

File address number 800

– I/O offset number – 000

---------------------------------- -------

XXXX XXXX 800

Begin RAM number + 000

---------------------------------- -------

2500 RAM address =

YYYY YYYY

800

If you have a file with absolute addressing and the programmer is using

the default (relative addressing), the file will download and the devices

will program without any error messages. However, the devices will not

be programmed correctly, because the RAM was not loaded with data at

the intended locations.

Tasks and Kits

3-18 ProMaster 2500 User Manual

Automatic RAM Fill

When a Task is run and it calls for a data file to be downloaded into RAM,

the 2500 will fill RAM with a specific data pattern depending on how this

field is set.

•

None

—RAM is not changed from its current state. The file will

download and write over the current contents.

•

Default

—RAM is initialized to the unprogrammed state for the

device type selected. This will not always be the same value since

some devices are all 0s and others are all 1s in their blank

(unprogrammed) state.

•

Specific

—When selected, a second field appears on the screen,

allowing you to choose a 2-digit hex value to use when filling RAM.

The other parameters listed in the Memory Device Parameters dialog box

are not normally used when programming with a 2500. Refer to

TaskLink’s online

Help

for a description of these parameters.

Data Sumcheck

This option enables TaskLink to perform a check on the integrity of the

data in RAM. We strongly recommend that you set this option to help

reduce programming errors.

When the sumcheck of the programmed device is entered in this field,

TaskLink compares it to the RAM sumcheck after downloading a file or

loading from a master device. If the sumchecks do not match, TaskLink’s

red warning box displays both sumchecks, and the Task stops. TaskLink

also monitors the RAM for any changes during programming.

This command is available only through the

Edit Task

dialog box. From

that box, select

<More>

and the parameter is displayed on the

Task Parameters

window.

Other TaskLink Parameters

Several non-mandatory parameters for both memory and logic devices

are available from other pull-down menus on the main screen. The next

sections describe these menus in the left-to-right order that they are

displayed on TaskLink’s main screen.

TaskLink supports a family of Data I/O programmers, each with unique

requirements. Only those commands that are used with the 2500 are

described in this manual. Information on all TaskLink commands is

available by pressing

to invoke TaskLink’s online Help.

Setup Menu Options

Most of the available choices from this pull-down menu have been

described in previous sections. The

Select Devices...

and

Select Process...

operations (see Figure 3-12) are the same commands that were selected in

the

Edit Task

dialog box to create a Task. Use these selections after a Task

has been loaded to select a device or process not included in the Task. Use

these commands when you want to run a job once and do not want to

create a new Task to do it.