STU-540 ROM 存储配置和操作

Description

ROM storage is allocated as follows:

Validate a stored ROM Image

Compute hash for required image

Compute the MD5 hash of the required image, for example by using an encryption library function.

Get hash for stored image

Retrieve the hash in two steps:

1. Request operation:

2. Get operation:

Upload image

Upload an image if no image is stored or the calculated and retrieved hash values do not match.
Image data is sent in three steps:

• Start ROM Image Data
• Write Image Data
• End Image Data

The Tablet interface simplifies the process with a single writeRomImage function.

Start ROM Data:

Write Image data:

End Image Data:

Start ROM Image Descriptors

PIN Pad

Slide Show

Key Pad

Signature Capture

Message Box

API Reference

Code illustration

Upload Image

The code illustrates uploading a SlideShow image

uploadImage(...)
{
writeImage = true;

// get the hash of the image stored in ROM (if it exists) 
tablet.setRomImageHash(operationModeType, imageType, imageNumber);
romImgHash = tablet.getRomImageHash();

if (romImgHash.result == 0)
  {
    // there is already an image on the tablet - check it is the right one// compute hash of the required image
    imgHash = getImageHash(bitmapData.data(), bitmapData.size());           
    if (imgHash == romImgHash.hash)
    {
      // image matches, no need to write it again
      writeImage = false;
    }
  }

if (writeImage)
  {
  romStartImageData = initializeSlideShow(encodingMode, imageType, imageNumber);    
  tablet.writeRomImage(romStartImageData, bitmapData.data(), bitmapData.size());
  }
}