Digital Design Errata and Clarifications ------------------------- Although we exerted tremendous effort to ensure this first edition book would not contain errors, a few errors may still manage to slip by. Below are mistakes found. Many thanks to the students and teachers who found them. Report errors to vahid@cs.ucr.edu. Chapter 2 EXERCISES * Page 93, Exercise 2.66 -- We do not presently know of a solution to this problem. The circuit in the solutions manual is not a correct solution to the stated problem. (Thank you to Greg Link of York College of Penn., 9/07) --------- Chapter 3 --------- * Page 106, Fig 3.24: In the timing diagram, Qm/Ds should return to 0 when Clk returns to 0, because D/Dm is 0 at that time. Presently, Qm/Ds is shown as staying at 1. This change does not impact the the main point of the example, namely the value of Qs. (Thank you to Mark Brehob of Univ. of Michigan, 5/07) * Page 101, Fig 3.15: In the timing diagram, R1 should be 0 from the beginning. (Thank you to Jose J. Farrington and Rafael Arce Nazario, University of Puerto Rico - Rio Piedras, 10/08) Chapter 4 --------- * Page 152: Fig 4.2 -- the four wires going to I3,I2,I1,I0 of R2 should be reversed. For example, R0's Q0 output should go through the inverter to I0 rather than to I3. (Thanks to Mahamed G. H. Omran of Gulf Univ. for Science and Technology in Kuwait). * Page 168: S = a'(b xor c)' + a(b xor c) should be: S = a'(b xor c) + a(b xor c)' (Thank you to Mark Brehob of Univ. of Michigan, 5/07) Chapter 5 --------- * Page 227, Example 5.1: Although not explicitly stated, we assume that the separation between two coins is very long compared to clock cycles. We also assume that the 8-bit input "a" continues to indicate the coin value for a long time (many clock cycles) after input "c" pulses. (Thank you to Mark Brehob of Univ. of Michigan, 5/07) * Page 246, Fig 5.32: The bottom-left arrow, from R in state A to Q in state B, should be deleted, because the assignment Q=R was moved to state B. The main point of the figure is still correct, but the extra arrow suggests a transfer that does not occur. (Thank you to Prof. Mahamed G. H. Omran of Gulf University for Science & Technology, 5/2010). * Page 290: The sentence "how to write a 9 and a 13 into locations 500 and 999" should be "how to write a 500 and a 999 into locations 9 and 13" (Thank you to Prof. Mahamed G. H. Omran of Gulf University for Science & Technology, 5/2010). Chapter 6 --------- * Page 357, first paragraph: The sentence that says "If the content's value is less than 128, then we know..." should have said "GREATER than the KEY" rather than "less than 128." We compare the contents with the key while trying to find the key, not with the address. Also, for the binary search as described, it should be clear that the sorting of items should be in ascending order, and thus, when the contents are greater, we need to look in 0 to 127. Likewise, for the next comparison, "If the value there is less than the key, we search 0 to 63; if greater, we search 65-127," the "less" should be "greater," and the "greater" should be "less". (Thank you to Anatolio Laschuk Porto Alegre in Brazil).