[previous] [next] [contents]    Work assignment: Scan Educator and the SN74BCT8244

The Scan Educator package is a public domain tool (developed by Texas Instruments) that provides a general introduction to the IEEE 1149.1 standard. This tool is particularly helpful to understand the operation of the BS infrastructure that is present in the SCOPE family of octal buffers and latches (SN74BCT8240 / 4 / 5 and SN74BCT8373 / 4). This assignment requests the student to carry out the following sequence of steps:

          Selecting the “TAP Control Testing” / “On Your Own” mode of operation and the SN74BCT8244 octal buffer as the octal in U2 (as shown in figure 1), specify and carry out the necessary operations to set neighbouring leds to opposite states (ON / OFF). Assume that both enable inputs (/1G and /2G) have a logic “1” applied.

Figure 1: Scan Educator - TAP Control Testing / On Your Own.

          Selecting the “Scan Control Mode Testing (Multiple Devices)” / “On Your Own” and again the SN74BCT8244 octal for U2, specify the operations required to observe the position (0/1) of the leftmost switches, using the octal buffer on the right. Assume that both enable inputs (/1G and /2G) of the octal buffer on the left have a logic “0” applied.

Figure 2: Scan Educator - Scan Control Mode Testing (Multiple Devices) / On Your Own.